Download fundamental concept of transition and inner

FUNDAMENTAL CONCEPT OF
TRANSITION
AND
INNER-TRANSITION ELEMENTS
FOR
CSIR/JRF/NET AND SET (CHEMICAL SCIENCES)
(PROBLEMS WITH ITS SOLUTIONS)
By
Dr Dinkar Malik
Department of Chemistry
Maharaj Singh College
Saharanpur (U.P)
2015
International E - Publication
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2015
All rights reserved. No part of this publication may be reproduced, stored, in a
retrieval system or transmitted, in any form or by any means, electronic,
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of the publisher.
ISBN: 978-93-84648-97-8
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PREFACE
This is the first time in my 10 year career that I have written a book, I'm proud to say that this is
one of the most in-depth, multi-dimensional review works of scientific researches. I have spent a
lot of time reading firstly the introductory-cum-tutorial part and analyzing how the author has
approached the subject of co-ordination chemistry.
Several books are available which provide guidance to students appearing for NET/JRF and
GATE examinations but there was a dearth of books which provide ample practice to the
students by incorporating numerous exercises. The net result is that these books contain very
little of the real content of chemistry –namely, the actual facts about the concepts of Chemistry.
The success of this e-book has been gratifying, for it tells us that teachers have found it effective
and that students have been found it useful and informative.
We have received numerous letters of request sent by the candidates aspiring for NET/JRF and
GATE examinations; the author has taken the initiative to write this book.
Our major objective is to develop confidence among the students who are appearing in NET/JRF
and GATE examinations after post graduation by providing them solved objective type questions
which covers the main aspect of the topic.
Keeping in view the need of the hour author presented a unique book which aims at further
enhancement of knowledge of the complex topics. The vast range of questions from a unique
perspective gives a real comprehension of the various topics related to the concerned
examinations.
Chemistry lies at the very heart of everything within us and around us. Its knowledge and the
chemical methods steadily increased over the centuries.
The author welcomes critical feedback on this book. Any suggestions for improvement of this
book are welcome and will be gratefully acknowledged.
Author
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BOOK READERSHIP
This book will be of interest to post graduate students and researchers who are preparing for
CSIR-NET/ JRF and GATE examinations. Advanced undergraduate students preparing for JAM
examination will also find this book useful. This book attempts to present chemistry in manner
that is sensible to the notice. The book is designed according to the new curriculum of CSIRNET/ JRF and GATE examinations.
A central theme of this book is a thoughtful, systematic approach to problems solving, learning
encompasses much more than simply memorizing facts.
ABOUT THE AUTHOR
Dr. Dinkar Malik, Assistant Professor, Maharaj Singh College, Saharanpur is erudite scholar and
chemist scientist. He has published more than 20 research papers in different reputed
International Journals. His area of research interests includes Synthesis, Characterization and
Biological aspects of Transition Metal Complexes.
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ACKNOWLEDGMENT
I wish to express deep sense of gratitude to Dr. K K Sharma, Principal, Maharaj Singh College
Saharanpur for his constant inspiration, intuitive guidance and timely help throughout the phase
of my work.
I am thankful to Dr. Vijai Malik, Assistant Professor, Department of Botany, Maharaj Singh
College Saharanpur for his constant guidance and motivation for writing this book.
I extend my thanks and best wishes to Dr. Sandeep Kumar, Assistant Professor, Department of
Chemistry, Maharaj Singh College Saharanpur and Dr. Punam Yadav, Assistant Professor,
Department of Chemistry, Maharaj Singh College Saharanpur for providing their guidance
advice and invaluable help and co-operation for writing this book.
The author is also thankful to my students especially Mr. Navdeep Arora and Mr. Arjun Tomar
who provide all type of help for the completion of this book.
I express my thanks to my wife Babita Malik and my loving children Anushka Malik and Abhay
Malik for their moral support, and constant encouragement helped me through the hard times.
My deepest appreciation is expressed to them for their understanding and inspiration. Without
their encouragement, I would not have been able to finish this work.
Last, but not the least, I bow my head to my parents for their affectionate love and blessings
towards me throughout my education, which has placed me at present level of academics career.
Dr Dinkar Malik
Department of Chemistry
Maharaj Singh College
Saharanpur (U.P)
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CONTENTS
Page No.
iii
iv
iv
v
Preface
Book Readership
About the Author
Acknowledgement
Chapter 1
Chemistry of Transition Elements
Critical Points
Multiple Choice Questions
Answers
Answers with Solutions
1-10
1
2-7
8
9-10
Chapter 2
Chemistry of Inner Transition Elements
Critical Points
Multiple Choice Questions
Answers
Answers with Solutions
11-23
11-12
13-20
21
22-23
Chapter 3
Reaction Mechanism of Transition Metal Complexes
Critical Points
Multiple Choice Questions
Answers
Answers with Solutions
24-35
24-25
26-32
33
34-35
Chapter 4
Metal π – Complexes (Carbonyls,Nitrosyls and Phosphines)
Critical Points
Multiple Choice Questions
Answers
Answers with Solutions
36-49
36-37
38-44
45
46-49
Chapter 5
Co-ordination Chemistry(Structure, Bonding, Color, Magnetic
Properties and Their Spectra)
50-61
Critical Points
50
Multiple Choice Questions
51-57
Answers
58
Answers with Solutions
59-61
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Chapter 1
Chemistry of Transition Elements
Critical Points:
(a)
Cu+ is diamagnetic while Co+2 is paramagnetic.
(b)
[Ti(H2O)6]+3 is colored while [Sc(H2O)6]+3 is colorless.
(c)
Ionization energy of 5d elements is greater than those of 3d and 4d elements.
(d)
Mercury is the only metal amongst transition elements which is liquid at 0oC due to
weak metallic bond.
(e)
Transition metals show variable oxidation states due to participation of ns and (n-1) d
electrons in bonding.
(f)
First ionization energy of 5d elements is higher than those of 3d and 4d elements due
to greater effective nuclear charge that is experienced over weak shielding of the
nucleus by 4f electrons.
(g)
Acidic character of oxides increases with increase in oxidation number
(h)
Elements from Cr to Cu have almost same atomic radii because successive addition
of d-electrons screened the outer electron (4s) from the inward pull of the nucleus.
(i)
In the highest oxidation states, the transition metal show acidic character and form
cationic complexes.
(j)
Misch metal is an alloy of rare earth metals with composition (Rare earth metals94.95%, Iron- 5% and trace amount of S, C, Ca, Al etc.
(k)
Nickel is purified by Mond’s Process.
100oC
Ni(CO)4 + Impurities
Ni + 4CO
0
Ni(CO)4
230 C
Ni + 4CO
(Pure Nickel)
Fe2O3 + 3H2
(l)
2Fe + 3H2O
(m)
22 Carat Gold is an alloy of Cu and Au.
(n)
The existence of Fe+2 and NO+ in nitroprusside ion, [Fe(CN)5NO]-2 can be
established by measuring the magnetic moment of the solid compound which should
correspond to Fe+2 (3d6) i.e. 4 unpaired electrons.
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Multiple Choice Questions
Q.1.
Q.2.
Q.3.
Q.4.
Q.5.
Q.6.
Q.7.
Q.8.
Q.9.
The number of manganese in tetrahedral and octahedral sites, respectively in Mn3O4 is :
(a) One Mn+2 and two Mn+3
(b) One Mn+3 and two Mn+2
(c) Two Mn+3 and one Mn+2
(d) Two Mn+2 and one Mn+3
Which Oxides will not give metal on heating?
(a) ZnO
(b) Ag2O
(c) HgO
(d)All of these
Which of following is least covalent or least acidic?
(a) VCl2
(b) VCl3
(c) VCl4
(d) VOCl3
In Na2[Fe(CN)5NO], sodium nitroprusside:
(a) Oxidation sate of Fe is +2
(b) This has NO+ as ligand
(c) Both (a) and (b) are correct
(d) None of the above is correct
Which of following complex is most easily reduced?
(a) V(CO)6
(b) Cr(CO)6
(c) Fe(CO)5
(d) Ni(CO)4
+2
+4
Ti is purple in color while Ti is colorless because:
(a) Ti+2 has 3d2 configuration
(b) Ti+4 has 3d2 configuration
(c) Ti+4 is a very small cation when compared to Ti+2 hence, does not absorb any
radiation.
(d) Ti+2 has one unpaired electron.
The atomic number of potassium is 19 and that of manganese is 25. Although [MnO4]has a dark violet color, that K+is colorless. This is due to the fact that
(a) Mn is a transition element, while Kis not.
(b) In Mn high positive oxidation state allows charge transfer transition.
(c) The effective atomic no. of Mn in [MnO4]- is 24 while for K+ , the effective atomic
no. is 18.
(d) [MnO4]- is negatively charged species while K+ has a positive charge.
Interstitial compounds are formed by
(a) Fe , Ni
(b) Fe, Co
(c) Co, Ni
(d) All of these
Select the correct statement(s).
(a) When FeCl3 solution is added to K4[Fe(CN)6] solution, in addition to FeIII[Fe(CN)6]-,
FeII[FeIII (CN)6]- is also formed due to side redox reaction.
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Q.10.
Q.11.
Q.12.
Q.13.
Q.14.
Q.15.
Q.16.
(b) When FeCl2 solution is added to K3[Fe(CN)6] solution, in addition to FeII[FeII (CN)6]FeIII[FeII (CN)6]- is also formed due to side redox reaction.
(c) FeIII[FeII (CN)6]- is diamagnetic, while FeII[FeIII (CN)6]- , is paramagnetic.
(d) FeIII[FeII (CN)6]- isparamagnetic, while FeII[FeIII (CN)6]- , isdiamagnetic
Which of the following statement is true?
(a) Cu+2 is colourless ion.
(b) Ions of d-block element are coloured due to d-d transition.
(c) Ions of f- block elements are colourless due to f-f- transition.
(d) [Sc(H2O)6]+3 , [Ti(H2O)6]+4are coloured complexes
Select the correct statement(s).
(a) Fe+2 is stable and Fe+3 is unstable in aerated water.
(b) Stabilities of variable oxidation state can be explained by standard electrode
potential.
(c) Cr+2 is stable and Cr+3 is unstable in aqueous solution.
(d) All of the above are correct statements.
AgCl and NaCl are colorless. NaBr and NaI are also colorless but AgBr and AgI are
colored. This is due to:
(a) Ag+ polarizes Br- and I(b) Ag+ has unpaired d- orbital.
(c) Ag+ depolarizes Br- and I(d) None of the above.
There are 3 unpaired electrons in [Co(H2O)6] +2 and calculated value of magnetic
momentis 3.87 B.M. which is quite different from the experimental value of 4.40 B.M.
This isbecause of:
(a) d-d* transition
(b) Change in orbital spin of the electron
(c) Increase in no. of unpaired electrons.
(d) Some contribution of the orbital motion of the electron to the magnetic moment.
Maximum oxidation of Os is
(a) +5
(b) +6
(c) +7
(d)+8
Select the incorrect statement(s)
(a) Cu+ is diamagnetic while Co+2 is paramagnetic.
(b) [Ti(H2O)6]+3 is colored while [Sc(H2O)6]+3 is colorless.
(c) Ionization energy of 5d elements are greater than those of 3d and 4d elements.
(d) Transition elements cannot form complexes,
Mercury is the only metal amongst transition elements which is liquid at 0oC. This is due
to its:
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Q.17.
Q.18.
Q.19.
Q.20.
Q.21.
Q.22.
Q.23.
(a) Weak metallic bond.
(b) High vapor pressure
(c) High ionization energy.
(d) Both (a) and (c).
The pair of compound having metals in their of highest oxidation is
(a) MnO2 , FeCl3
(b) [NiCl4]-2, CoCl4(c) MnO4- CrO2Cl2
(d) [Fe(CN)6]-3 , Co(CN)3
Different (variable) oxidation state is shown by transition element. It is due to the fact
(a) ns electrons may be excited to (n-1) d orbitals.
(b) (n-1) d electrons may be excited to ns orbitals.
(c) (n-1) d electron may get involved along with ns electron in bonding.
(d) None of the above fact is correct.
First ionization energy of 5d elements is higher than those of 3d and 4d elements. This
is due to:
(a) Greater effective nuclear charge acting on outer valance electrons.
(b) Greater effective nuclear charge is experienced because of weak shielding of the
nucleus by 4f electrons.
(c) Both (a) and (b)
(d) None of the above.
When Na2CO3 is added to an aqueous solution of CuSO4, which of the following is
precipitated?
(a) Cu(CO3)2
(b) Cu(OH)(CO3)
(c) Cu(HCO3)2
(d) Cu(OH)2
A transition metal complex shows a magnetic moment of 5.20 BM at room temperature.
The number of unpaired electron on the metal is
(a) 3
(b) 4
(c) 5
(d) 2
The radii of the elements from Cr to Cu are very closed to one another. This is due to
(a) Lanthanide contraction
(b) Atomic radii do not remain constant but decrease in normal gradation
(c) The fact that successive addition of d-electrons screened the outer electron (4s) from
the inward pull of the nucleus.
(d) Increase in radii due to increase in ‘n’ is compensated by decrease in radii due to
increase in ‘Z’.
The number of unpaired electrons present in Cr+2, Fe+2, Co+2 and Ni+2 are respectively
(a) 2, 3, 4 and 4
(b) 4, 4, 3 and 2
(c) 4, 4 ,2 and 3
(d) 1, 4, 2 and 3
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Q.24. For [Ti(H2O)6]+3 absorption maximum due to d-d transition is found at 20000 cm-1.
Therefore, the crystal field stabilization energy is:
(b) 8000 cm-1
(a) -20000 cm-1
(c) 4/9×20000cm-1
(d) -8000 cm-1
Q.25 In context with the transition elements which of the following statements is incorrect:
(a) In addition to the normal oxidation state, the zero oxidation state is also shown by
these elements in complexes.
(b) In the highest oxidation states, the transition metal show basic character and form
cationic complexes.
(c) In the highest oxidation states , the first transition elements (Sc to Mn) all the 4s and
3d electrons are used for bonding.
(d) Once the d5 configuration is exceeded, the tendency to involve all the 3d electrons in
bonding decreases.
Q.26. Highest (+7) oxidation is shown by:
(a) Co
(b) Cr
(c). V
(d).Mn
+2
Q.27. In a raction the Ferrous (Fe ) ion is oxidized to Ferric (Fe+3) ion. The equivalent weight of
the ion in the above reaction is equal to
(a) Half of the atomic weight
(b) 1/5 of the atomic weight
(c) The atomic weight
(d) Twice the atomic weight
Q.28. One of the following metal forms a volatile carbonile compound and this property is taken
advantage for its extraction. The metal is
(a) Fe
(b) Ni
(c) Co
(d) W
Q.29. Which of the following transition metal is present in misch metal?
(a) La
(b) Sc
(c) Ni
(d) Cr
Q.30. The atomic number of Vanadium (V), Chromium (Cr), Manganese (Mn) and Iron (Fe)
are respectively 23, 24, 25 and 26. Which one of these may be expected to have the
highest second ionisation energy?
(a) V
(b) Cr
(c) Mn
(d) Fe
Q.31. Which of the following ions form most stable complex compound:
(a) Cu+2
(b) Ni+2
(c) Fe+
(d) Mn+2
Q.32. Which transition metal reduces steam to evolve hydrogen:
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Q.33.
Q.34.
Q.35.
Q.36.
Q.37.
Q.38.
Q.39.
Q.40.
(a) Mn
(b) Fe
(c) Cu
(d) Pt
Which of the following weighs less when weighed in magnetic field:
(a) VCl3
(b) ScCl3
(c) TiCl3
(d) FeCl3
+3
+3
+3
+3
Arrange Ce , La , Pm and Yb in increasing order of their ionic radii:
(a) Yb+3 < Pm+3 < Ce+3 < La +3
(b) Ce+3 < Yb+3 < Pm+3 < La +3
(c) Yb+3 < Pm+3 <La +3< Ce+3
(d) Pm+3 <La +3< Ce+3< Yb+3
In following reaction
yMnO4+ xH+ +
C2O4-2
yMn++ + 2CO2 + x/2 H2O
x and y are :
(a) 2 and 16
(b) 16 and 2
(c) 8 and 16
(d) 5 and 2
Formula of thiosulphate, mangnate and arsenate respectively are:
(a) S4O6-2 , MnO4-2, AsO3-3
(b) S2O3-2, MnO4-2, AsO4-3
(c) S2O3-2, MnO4-2, AsO3-3
(d) S4O6-2, MnO4-2, AsO4-3
Which of the following is not an element?
(a) Graphite
(b) Diamond
(c) 22-Carat Gold
(d) Rhombic sulphur
The number of moles of KMnO4 that will be needed to react completely with one mole of
ferrous oxalate Fe(C2O4) in acidic solution is
(a) 3/5
(b) 2/5
(c) 4/5
(d)1
Amongst following the lowest degree of paramagnetism per mole of the compound at
298K will be shown by:
(a) MnSO4 . 4H2O
(b) CuSO4.5H2O
(c) FeSO4.6H2O
(d) FeSO4.5H2O
In Nitroprusside ion, the iron and NO exit as FeII and NO+ rather than FeIII and NO.
These forms can be differentiated by:
(a) Estimating the concentration of iron
(b) Measuring the concentration of CN(c) Measuring the solid state magnetic moment
(d) Thermally decomposing the compound
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Q.41. Which of the following pairs of metals is purified by Van Arkel Method?
(a) Ni and Fe
(b) Ga and In
(c) Zr and Ti
(d) Ag and Au
Q. 42 The acidic, basic or amphoteric nature of Mn2O7, V2O5 and CrO are respectively
(a) acidic, acidic and basic
(b) basic, amphoteric and acidic
(c) acidic, amphoteric and basic
(d) acidic, basic and amphoteric
Q.43. Sulphur trioxide can be obtained by which of the following reaction \
∆
Δ
(b) Fe2 (SO4)3
(a) CaSO4 + C
∆
∆
(c) S + H2SO4
(d) H2SO4 + PCl5
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Answers
1- (a)
2-(a)
3-(a)
4-(c)
5-(a)
6- (a)
7- (b)
8-(d)
9-(a,b,c)
10-(b)
11-(b)
12-(a)
13- (d)
14-(d)
15-(d)
16-(a)
17- (c)
18-(c)
19- (b)
20-(c)
21-(b)
22-(c)
23- (b)
24-(d)
25- (b)
26-(d)
27-(c)
28-(b)
29-(a)
30-(b)
31- (a)
32-(b)
33-(b)
34-(a)
35-(b)
36-(b)
37- (c)
38-(a)
39-(b)
40-(c)
41- (c)
42- (c)
43- (b)
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Answers with solution
12-
(a)
(a)
3-
(a)
4-
(c)
56-
(a)
(a)
78-
(b)
(d)
9101112131415161718192021-
22-
[ Spinal structure of Mn3O4 has one tetrahedral and two octahedral sites].
[ Metal oxides below H in electrochemical series decompose heating].
HgO
Hg
+ O2
ZnO
No reaction
Ag2O
Ag
+ O2
[ Covalent character is directly proportional to the charge on the ion].
V+2 < V+3 < V+4 < V+5
So VCl2 is least covalent and least acidic. ]
NO
NO+ `+
eFe+3 + eFe+2
[ V(CO)6] has 17 valance electron hence it can be easily reduced]
[Ti+2 has two unpaired electron in 3d sub-shell and thus d-d* transition due to
absorption of light in visible range however Ti+4 has all paired electron,
therefore it is colourless].
[Some small size non metal like C,H,N etc. fit into the crystal lattice of transitions
metals to form interstitial compounds]
(a, b, c)
(b)
(b)
(a)
(d)
[ Magnetic moment shows difference due to orbital contribution along with spin
contribution]
(d)
(d)
[ Transition metal forms complexes due to their variable oxidation states]
(a)
(c)
(c)
(b)
(c)
(b)
[ µ spin = √ n(n+2) B.M, According to spin only magnetic moment the value is 4.9
B.M. but the slightly higher value (5.2 B.M) will be due to the orbital
contribution]
(c)
[ Due to screening effect ]
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2324-
(b)
(d)
25-
(b)
262728-
(d)
(c)
(b)
29-
(a)
3031323334353637383940-
(b)
(a)
(b)
(b)
(a)
(b)
(b)
(c)
(a)
(b)
(c)
414243-
(c)
(c)
(b)
2
10 Dq = 20000 cm-1 ( According to 2T2g
Eg transition)
-1
Dq = 2000 cm
CFSE = -4 Dq
= -4 × 2000 cm-1
= -8000 cm-1
[In the highest oxidation states, the transition metal show acidic character and
form cationic complexes].
[ Equivalent weight = Molecular weight because n-factor is one]
[ Ni + 4CO 100oC Ni(CO)4 + Impurities
Ni(CO)4
2300C
Ni + 4CO
(Pure Nickel)
Ni is purified by Mond’s Process]
[ Misch metal is an alloy of rare earth metals with composition ( Rare earth
metals- 94.95%, Iron- 5% and trace amount of S, C, Ca, Al etc.]
[ Due to d5 configuration]
[ Due to small size of Cu++ ion]
[ 2Fe + 3H2O
Fe2O3 + 3H2]
[2MnO4- + 16H+
+ C2O4-2
2Mn++ + 2CO2 +8 H2O]
[ 22 Carat Gold is an alloy of Cu and Au]
[ 3MnO4- + 5Fe+2 + 5C2O4-2 + 24H+
3Mn+2 + 5 Fe+3 + 10 CO2 + 10H2O]
[ It has only one unpaired electron]
[ The existence of Fe+2 and NO+ in nitroprusside ion,[Fe(CN)5NO]-2 can be
established by measuring the magnetic moment of the solid compound which
should correspond to Fe+2 (3d6) i.e. 4 unpaired electrons}
[ Acidic character of oxides increases with increase in oxidation number]
[ Fe2(SO4)3
∆
Fe2O3 + SO3]
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Chapter 2
Chemistry of Inner Transition Elements
Critical Points:
(a)
General electronic configuration – (n-2)f 1-14 (n-1)d0-1 ns2
Lanthanides and Actinides are collectively known as f block elements because last
(b)
electron enters into f orbital of the antepenultimate shell.
(c)
The elements with atomic number 58 to 71 are called Lanthanides (Ce to Lu).
(d)
The elements with atomic number 90 to 103 are called Actinides (Th to Lr).
(e)
The regular decrease in the size of lanthanide ions from La+3 to Lu+3 due to increase
in effective nuclear charge is known as Lanthanide Contraction.
(f)
Consequences of Lanthanide Contraction :
(a) Similarity in size of some elements of IInd and IIIrd transition series e.g. Zr-Hf,
Nb-Ta and Mo-W are known as twins.
(b) Difficulty in separation of Lanthanides due to their similar chemical properties
and similar size.
(c) The covalent character of hydroxides of lanthanides increases as the size
decreases from La+3 to Lu+3.
(d) The basic strength of hydroxides of lanthanides decreases with decreases in size
from La+3 to Lu+3.
(e) Tendency to form stable complexes from La+3 to Lu+3 increases as the size
decreases in that order.
7.
There is a slight increase in electro negativity of the trivalent ions from La to Lu.
8.
Sm+2, Eu+2 and Yb+2 are good reducing agent.
9.
Ce+4 behaves as a very good oxidizing agent.
10. β- diketone complexes of Eu+3 and Pr+3 are known as shift reagents e.g. Eu(dpm)2 and
Eu(fod)3.
11. Shift reagents provide a method for spreading out NMR absorption patterns without
increasing the strength of the applied magnetic field.
12. Oxocations of actinides are stable in aqueous solution due to their high charge density
e.g. UO2+2 however oxocations of lanthanides are unstable in aqueous solution.
13. The absorption bands of f -block elements are sharp line like peak due to weak metalligand interaction.
14. Lanthanides have lesser tendency to form complexes than transition metals.
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15.
16.
17.
Actinides have greater tendency to form complexes because of higher nuclear charge
and greater multiplicity of oxidation states as compared to lanthanides.
Ion exchange method is the most effective and rapid method for the separation and
purification of lanthanides.
The magnetic moment of Eu+3 and Sm+3 complexes are higher than those of
calculated by spin only values.
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Multiple Choice Questions
Q.1
Q.2
Q.3
Q.4
Q.5
Q.6
Q.7
Elements from atomic no 58 (Ce) to 71 (Lu) are:
(a)
Actinides
(b)
Lanthanides
(c)
Transition Metals
(d)
Alkali Metals
In a nuclear reactor oxides of which of the following metals are used as a fuel material?
(a) Uranium 2- Thorium 3- Actinium 4- Plutonium
Select the correct answer using the codes given below:
(a)
1 and 3
(b)
2 and 3
(c)
1, 2 and 4
(d)
2, 3 and 4
Which of the following elements are soluble in liquid ammonia?
(a)
Pm and Sm
(b)
Ce and Ho
(c)
Tm and Lu
(d)
Eu and Yb
The general electronic configuration of inner transition metals is:
(a)
(n-2)f 1-14
(b)
(n-2) f1-14 (n-1) d0 ns2
(c)
(n-2)f 1-14 (n-1)d0-1 ns2
(d)
The electronic configuration of Gadolinium is:
(a)
4f6 5d0 6s2
(b)
(n-2) f 1-14 ns2
4f7 6d0 6s2
4f8 5d1 6s2
(c)
4f7 5d1 6s2
(d)
Eu and Yb elements show similar reactivity as that of:
(a)
Li
(b)
Na
(c)
Tl
(d)
Ba
M+2 ions of lanthanide can be easily converted into M+3 ions by
(a)
Loss of electrons through oxidation
(b)
Gain of electrons through reduction
(c)
By oxidation and reduction both
(d)
None of them
Q.8
The most common oxidation state of lanthanides is:
(a)
+4
(b)
+3
(c)
+6
Q.9
Color in transition metal compounds is attributed to:
(a)
Small size of metal ions
(b)
Absorption of light UV region
(c)
Complete (ns) sub shell
(d)
Incomplete (n-1) d sub shell
Q.10 Which of the following ion does not form colored complex?
(a)
Ni ((II)
(b) Sc (II)
(c)
Fe (II)
(d)
+2
(d)
Cr (VI)
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Q.11
Q.12
Q.13
Which element among lanthanides has smallest atomic radius?
(a)
Cerium
(b)
Holmium
(c)
Europium
(d)
Gadolinium
One
of
the
consequences
of
lanthanide
(a)
Zr & Zn have the some oxidation state
(b)
Zr & Hf have almost same atomic radius
(c)
Zr & Nb have smaller oxidation state
(d)
Zn & Dy have almost same atomic radius
M+4 ions of Lanthanides can be converted into M+3 ions by
contraction
is:
(a)
Gain of electron through Oxidation
(b)
Loss of electronthrough Reduction
(c)
Loss of electron through Oxidation
(d)
Gain of electron through Reduction
Q.14 The coordination number of Ce in Cerric ammonium nitrate is:
(a)
10
(b)
11
(c)
12
(d)
14
Q.15 Cerric ammonium nitrate has coordination number 12 because
(a)
NO3 behaves as mono dentate ligand
(b)
NO3 behaves as bi dentate ligand
(c)
NO3 behaves as mono dentate as well as bi dentate ligand
(d)
NO3 is neither mono dentate nor bi dentate ligand
Q.16According to VSEPR theory the structure of Cerric ammonium Nirate is:
(a)
Distorted Icosahedral
(b)
Symmetrical Octahedral
(c)
Symmetrical Icosahedral
(d)
Distorted Octahedral
Q.17 The distortion in the structure of Cerric Ammonium Nitrate is due to:
(a)
Bi dentate nitrate ligand
(b)
Mono dentate nitrate ligand
(c)
Bi dentate nitrite ligand
(d)
Mono dentate nitrite ligand
Q.18 The colour of Cerric Ammonium Nitrate is due to:
(a)
d-d transition
(b)
Metal to Ligand charge transfer transition
(c)
Crystal field transition
(d)
Ligand to Metal charge transfer transition
Q.19 The basic character of Lanthanides decreases from
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(a)
Lu (OH)3 to La(OH)3
(b)
La(OH)3 to Lu (OH)3
(c)
Increases from La(OH)3 to Gd(OH)3 and then decreases up to Lu (OH)3
(d)
Decreases from La(OH)3 to Gd(OH)3 and then Increases up to Lu (OH)3
Q. 20 Consider the following statement for (NH4)2[Ce(NO3)6] (Z)
A. Co ordination number of Ce is 12
B. Z is paramagnetic in nature
C. Z is an oxidizing agent
The correct statements are:
(a)
B and C
(b)
A, B and C
(c)
A and B
(d)
A and C
Q.21 The separation of Lanthanides is possible by:
(a)
Normal method
(b)
Ion - exchange method
(c)
Permutit method
(d)
Chromatographic method
Q.22 The absorption bands in Lanthanides are:
(a)
Broad peak
(b)
Sharp line like peak
(c)
Diffused peak
(d)
Broad and sharp peak
Q. 23 The least basic among the following is:
(a)
Al(OH)3
(b)
La(OH)3
(c)
Lu(OH)3
(d)
Ce(OH)3
Q. 24 The total magnetic moment of lanthanides with a lander’s splitting factor follows
the relation:
(a)
µ = g √J(J+1)
(b)
µ = √n (n+2)
(c)
µ = √ 4S(S+1) +L(L+1)
(d)
None
Q. 25 The pair of lanthanides with the highest third ionization energy is:
(a)
Eu,Gd
(b)
Eu,Yb
(c)
Dy,Yb
(d)
Lu,Yb
Q. 26 Which of the following ion is colorless?
(a)
Pm+3
(b)
Ce+3
(c)
Sm+3
(d)
Eu+3
Q. 27 Which of the following lanthanide ion has highest magnetic moment?
(a)
Dy+3
(b)
Gd+3
(c)
Sm+3
(d)
Tb+3
Q. 28 Consider the following statements:
1. The size of the lanthanides M+3 ions decreases as the atomic number of M
increases.
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Q. 29
Q. 30
Q. 31
Q. 32
Q. 33
Q. 34
Q. 35
Q, 36
2. Electronic spectra of lanthanides show very broad bands.
3. Co-ordination number six is very common among lanthanide complexes.
Which of the following statements given above is/are correct?
(a)
1 and 2
(b)
1 and 3
(c)
1,2 and 3
(d)
1 only
The lanthanide (III) ion having the highest partition coefficient between tri-n- butyl
Phosphate and concentrated HNO3 is:
(b)
Nd+3
(a)
Eu+3
(d)
La+3
(c)
Lu+3
The correct sequence of ionic radii in increasing order of the given lanthanide cations is :
(b)
Pm+3< La+3< Ce+3< Yb+3
(a)
Yb+3< Pm+3< Ce+3< La+3
+3
+3
+3
+3
(c)
Ce < Yb < Pm < La
(d)
Yb+3< Pm+3< La+3< Ce+3
In a nuclear reactor, oxides of which of the following metals are used as a fuel material?
(a) U
2. Th
3. Ac
4. Pu
Select the correct answer using the codes given below:
(a)
1 and 3
(b)
2 and 3
(c)
1,2 and 4
(d)
2,3 and 4
Fast breeder reactors are based on which one of the following?
(a)
Conversion of U238 to Pu239 and removing the moderator
(b)
Conversion of Th232 to Pu239 and using the moderator
(c)
Conversion of Th232 to U235 and removing the coolant
(d)
Conversion of U238 to U233 and removing the coolant
Which of the following are fissionable elements”
(a) 92U238
2. 92U235
3. 94Pu239
4. 94Pu239
Select the correct answer using the codes given below:
(a)
1 and 3
(b)
1 and 2
(c)
1,3 and 4
(d)
2,3 and 4
The ligand field bands of lanthanide complexes are generally sharp line like peak than
those of transition metal complexes because:
(a)
Transitions are allowed for lanthanide complexes
(b)
f orbital’s have higher energy than d orbital’s
(c)
f orbital’s compared to d orbital’s interact less effectively with ligands
(d)
Intensity of the bands is higher for lanthanides complexes
Which one of the following shows the highest solubility in hot concentrated NaOH?
(a)
Nd(OH)3
(b)
La(OH)3
(c)
Lu(OH)3
(d)
Sm(OH)3
Consider the ions Eu (III), Gd(III), Sm(III) and Lu(III). The observed and calculated
Magnetic Moment is closest for the pair:
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(a)
Lu(III),Gd(III)
(b)
Eu(III),Lu(III)
(c)
Sm(III),Gd(III)
(d)
Eu(III),Sm(III)
Q. 37 Which of the following ligand forms a stable complex with Ln+3 ion?
(a)
C2H4
(b)
H2O
(c)
PPh3
(d)
CO
Q. 38 Identify the pairs in which the covalent radii of elements are almost similar:
1.Nb,Ta
2. Mo,W
3. La.Lu
4. Sc,Y
(a)
1 and 2 only
(b)
1 and 3 only
(c)
2 and 3 only
(d)
3 and 4 only
Q. 39 Consider the following lanthanide (III) ions:
1. Nd(III)
2. Dy(III)
3. Gd(III)
The magnetic moment close to spin only value is (are) for:
(a)
1 and 3 only
(b)
1 and 3 only
(c)
3 only
(d)
2 and 3 only
Q. 40 The ground state term symbol for Nb ( atomic number 41) is 6D.The electronic
configuration corresponding to this term symbol is:
(a)
[Kr] 4d35s2
(b) [Kr] 4d45s1
(c)
[Kr] 4d55s0
(d) [Kr] 4d35s15p1
Q. 41 Uranium exhibits several oxidation states because:
(a)
It is an inner transition element
(b)
5f orbital participate in bonding
(c)
Its atomic weight is high
(d)
It forms strong bond with oxygen
Q. 42 Which one of the following pairs absorb radiations in UV and IR region respectively:
1. Sm,Yb
2. Ce,Yb
3. La.Lu
4. Gd,Lu
(a)
1 and 2 only
(b)
1 and 3 only
(c)
2 and 3 only
(d)
2 only
Q. 43 Which of the following compound shows a charge transfer band?
(a)
Lanthanum nitrate
(b)
Cerric ammonium nitrate
(c)
Mangnese (II) acetate
(d)
Copper (II) sulphate
Q. 44 Among the following statements, identify the correct ones for the complexes of
lanthanide (III) ions:
(a)
Metal-ligand bond is significantly ionic.
(b)
Complexes rarely show isomerism.
(c)
The co-ordination number is not more than 8.
(d)
The magnetic moment are not accounted even approximately by spin only value
for majority of lanthanides.
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(a)
1,2 and 3
(b)
1 and 4
(c)
1,2 and 4
(d)
2 and 3
Q. 45 Statement I: The sizes of Zr and Hf are similar.
Statement II: Size of Hf is affected by lanthanide contraction.
(a) Statement I and II are correct and II is correct explanation of I.
(b) Statement I and II are correct but II is not correct explanation of I.
(c) Statement I is correct and II is incorrect.
(d) Statement I and II both are incorrect.
Q. 46 The electronic configuration of Gadolinium Is [Xe] 4f75d16s2, where as that of
Gd+2 is:
(b)
[Xe] 4f65d06s2
(a)
[Xe] 4f55d06s2
6 1 1
(c
[Xe] 4f 5d 6s
(d)
[Xe] 4f75d16s0
Q. 47 Uranium fluoride co-precipitate with:
(a)
CaF2
(b)
AgF
(c)
MgF2
(d)
LiF
Q. 48 The actual magnetic moment shows a large deviation from the spin only formula in
case of:
(a)
Ti+3
(b)
V+3
(c)
Gd+3
(d)
Sm+3
Q. 49 The coordination number and geometry of Ce in [Ce(NO3)6]2- are respectively:
(a)
6 and octahedron
(b)
6 and trigonal prism
(c)
8 and cubic
(d)
12 and icosahedron
Q. 50 Statement I:
U (VI) is more stable than Nd(VI).
Statement II: The valence electron in U are in 5f,6d and 7sorbital’s.
(a)
Statement I and II are correct and II is correct explanation of I.
(b)
Statement I and II are correct but II is not correct explanation of I.
(c)
Statement I is correct and II is incorrect.
(d)
Statement I and II both are incorrect.
Q. 51 The ground state forms of Sm+3 and Eu+3 respectively are:
7
6
(a)
F0 and 6H5/2
(b)
H5/2 and 7F0
2
7
(c)
F5/2 and 5I4
(d)
F6 and 2F7/2
Q. 52 The nuclides among the following capable of undergoing fission by thermal neutrons are:
233
1.
U
2.235U
3.239Pu
4.232Th
(a)
1,2 and 4
(b)
1,3 and 4
(c)
2,3 and 4
(d)
1,2 and 3
Q. 53 A comparison of the valance electron configuration of the elements, Sm and Eu suggests
that:
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Q. 54
Q. 55
Q. 56
Q. 57
Q. 58
Q. 59
Q. 60
Q. 61
Q. 62
(a)
Sm is a better one electron reductant than Eu
(b)
Sm is a better one electron oxidant than Eu
(c)
Facile oxidation state is +2 for both the elements
(d)
Both of these display similar redox behavior
Hindered β- diketones like dpmH (dpmH = dipivaloylmethane) are used for the
separation of Lanthanides because complexes formed with dpmH can be separated by:
(a)
Gel permeation chromatography
(b)
Gas chromatography
(c)
Gel filtration chromatography
(d)
Ion exchange chromatography
Gel permeation chromatography can be used to separate which of the following:
A. Lanthanides
B. Alkaline earths
C. Fatty acids
D. Low molecular weight peptides
The correct answer is:
(a)
A and B
(b)
B and C
(c)
C and D
(d)
A and D
Which one among the following lanthanides exhibits radioactive nature?
(a)
Sm
(b)
Eu
(c)
Gd
(d)
Pm
Which one among the following element belongs to actinides series?
(a)
Sm
(b)
Eu
(c)
Cm
(d)
Pm
The most stable oxidation state for U is:
(a)
+3
(b)
+4
(c)
+5
(d)
+6
In nature Thorium exists as:
231
233
(a)
Th
(b)
Th
232
234Th
(c)
Th
(d)
In which of the following compound stochiometry is not followed:
(a)
UO2
(b)
U3O8
(c)
UO4
(d)
UO3
Among the following compounds, the powerful fluorinating agent is:
(a)
UF3
(b)
UF4
(c)
UF6
(d)
UF5
Which one of the following is a valuable laboratory source of α- particle:
(a)
Np
(b)
Pu
(c)
U
(d)
Am
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Q. 63 Actinides have a greater tendency to form complexes as compared to lanthanides because
actinides have:
(a)
Large size of ions
(b)
Low multiplicity of atoms
(c)
High nuclear charge
(d)
Low nuclear charge
Q. 64 The structure of Cerric ammonium nitrate has:
(a)
12 faces and 20 vertices
(b)
12 faces and 12 vertices
(c)
20 faces and 20 vertices
(d)
20 faces and 12 vertices
Q. 65 Metal electrides of Lanthanum and Cerium have:
(a)
M+3 and (I2-)e- ions
(b)
M+3 and I2- ions
(c)
M+3 and I- ions
(d)
M+3 and I2 ions
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Answers
1- (b),
2- (c),
3- (d),
4- (c),
5- (c),
6- (d),
7- (a),
8 - (b),
9 - (d),
10 - (d),
11 - (b),
12 - (b),
13 - (d),
14 -(c),
15 - (b),
16 – (a),
17 – (a),
18 - (d),
19- (b),
20 - (d),
21 – (b),
22- (b),
23- (a),
24- (a),
25-(b),
26- (b),
27- (b),
28- (d),
29- (c),
30- (a),
31- (c),
32 – (a),
33 –(b),
34- (c),
35- (c),
36- (a),
37- (d),
38- (a),
39- (c),
40- (b),
41- (b),
42 – (d),
43- (b),
44- (c),
45- (a),
46 – (d),
47 – (a),
48- (d),
49- (d),
50 –(b),
51 – (b),
52- (d),
53- (b),
54- (b),
55 - (c),
56- (d),
57- (c),
58 - (d),
59 – (c),
60 - (c),
61 - (c),
62 - (d),
63 – (c),
64- (a),
65-
(a).
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Answers with solution
13478910 11 12 13 14 18 1920 22232425262728293031343536-
(b) , 2- (c) ,
(d) [ These elements are soluble in ammonia like Ist and IInd group elements except Be]
(c),
5 – (c),
6 –(d),
+3
(a) [ M ions of Lanthanides has maximum stability]
(b),
(d)[ Incomplete (n-1)d- sub shell or d-d transition ]
(d) [ absence of unpaired electrons]
(b) [size decreases with increase in atomic number in Lanthanide series due to
Lanthanide Contraction]
(b) [ Zr-Hf, Nb-Ta and Mo-W have almost same atomic radius due to Lanthanide
Contraction]
(d) [ M+3 ions of Lanthanides are most stable hence M+4 ion can be converted into M+3
ion through reduction ]
(c),
15 - (b),
16 – (a),
17 – (a),
(d) [because Ce is in highest Oxidation State (IV) in Cerric Ammonium Nitrate]
(b) [Due to Lanthanide Contraction or due to decrease in size of Lanthanides]
(d),
21 – (b),
(b)[Sharp line like peak due to weak metal- ligand interaction]
(a) [ amphoteric whereas hydroxides of lanthanides are basic]
(a),
(b) [ Eu++ 4f7- Half filled - stable and Yb++ 4f14 - completely filled- Stable]
(b) [Pm+3, Sm+3 and Eu+3 are colored due to the presence of unpaired electrons
however Ce+3and Yb+3 do not absorb light in visible region]
(b) [Gd+3 has maximum number of unpaired electrons i.e. 7]
(d) [ Absorption bands of lanthanides are sharp line like peak. The most common
co-ordination number of lanthanides are 7,8 and 9]
(c) [ Smaller will be the size of lanthanide (III) ion, higher will be the
partition coefficient]
(a) [ Size decreases in a lanthanide series due to lanthanide contraction ]
(c),
32 –(a),
33 –(b),
(c) [ f-orbital’s interact less effectively hence they have sharp line like peak]
(c) [ Since size of Lu+3 is smallest, therefore Lu(OH)3complex will be formed most
easily with NaOH and dissolve in it]
(a) [ The electronic configuration of Gd+3 and Lu+3 are f7 and f14 respectively, for these
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37383940414344-
45484952-
5354565763 –
6465-
ions angular momentum is zero and there is no orbital contribution therefore
calculated and observed values of magnetic moment are closest for this pair]
(d) [ Strongest ligand amongst the given ligand]
(a) [ Almost similar radii due to lanthanide contraction]
(c),
(b) [ 2s+1=6, i.e. s=5 unpaired electron. For D, term L= 2 therefore electronic
configuration is{Kr} 4d45s1]
(b),
42 –(d),
+4
(b) [ Ce ion shows Ligand- Metal charge transfer spectra]
(c)[ Due to large size, un-availability of orbitals for bonding and high basicity
lanthanides rarely show isomerism. Co-ordination numbers are generally more than
8]
(a),
46 – (d),
47 – (a),
+3
+3
(d) [ Eu and Sm due to spin orbital coupling]
(d),
50 –(b),
51 – (b),
(d), [ Very heavy nuclei have low binding energy per nucleon than nuclei with
intermediate mass. 235U and 239U are used as fission by thermal neutron. All
isotopes of Pu are fissile and used asa nuclear fuel]
(b)[ Sm is a better oxidant (O.A) due to d6 configuration]
(b),
55 - (c),
(d), [ Among lanthanides only Pm is radioactive in nature]
(c),
58 - (d),
59 – (c),
60 - (c),
61 - (c),
62 - (d),
(c),
(a) [ Cerric ammonium nitrate has distorted icosahedral structure with 12 faces and 20
Vertices]
(a) [Metal electrides (LaI2 and CeI2) are good conductor of electricity and exists in the
form of M+3oxidation state and have anionic electron]
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Chapter 3
Reaction Mechanism of Transition Metal Complexes
Critical Points:
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
(k)
(l)
(m)
(n)
(o)
(p)
SN1CB mechanism stands for substitution, nucleophilic, unimolecular, conjugate
base.
Fluxional molecules undergo deformational rearrangements in which the atom
actually interchanges their places with one another e.g. PF5.
A class of fluxional molecule of great importance is those with trigonal bipyramidal
configuration. When all the five appended groups are identical single atoms, as in
AB5, the symmetry of the molecule D3n.
The process in which one of the more symmetrical forms (TBP for the 5-co-ordinated
complex) changes to another (square pyramidal) and then back to an equivalent form
in which the interchange of the ligands take place is called polytonal arrangement.
5-co-ordinated and 8-co-ordinated complexes are generally fluxional even at low
temperature.
The octahedral complexes, in general, are not fluxional.
The non-rigid molecules in which two or more configurations are not chemically
equivalent and the process of inter conversion is called isomerism or tautomerism.
The non-rigid molecules in which two or more configurations are chemically
equivalent and such non-rigid molecules are called fluxional.
In an inner sphere redox reaction the two metal ions are connected in the activated
complex through a bridging ligand common to both co-ordination shells.
In an outer sphere redox reaction electron transfer occur through the intact coordination shells of the metal ions.
The arrangement of stabilities of high spin complexes of the ions between Mn+2 and
Zn*2 with a ligand is known as Irving-William order of stabilityMn+2< Fe+2<Co+2< Ni+2< Cu+2< Zn+2
Most of the inorganic reactions are ionic in nature
In the dissociative mechanism of octahedral complexes, the more stable intermediate
formed is square pyramidal.
SN1 mechanism is favored when oxidation state of metal atom is less.
In SN1 mechanism, the rate determining slowest step is metal-ligand bond breaking
step.
In SN1 mechanism the co-ordination no. of the complex is decreased from 6 to 5.
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(q)
(r)
(s)
(t)
(u)
(v)
(w)
(x)
(y)
(z)
(aa)
(bb)
(cc)
(dd)
In SN2mechanism pentagonal bi pyramidal (PBP) intermediate is formed, while
octahedral wedge intermediate is more common.
Trans- effect is explained by polarization theory.
With the increase in trans- effect of ligands, the rate of reaction also increases.
For inner sphere mechanism electron transfer reactions, one complex should be inert
and other should be labile.
For outer sphere mechanism electron transfer reactions, both the complexes should be
labile.
For inner sphere mechanism, the inert complex should have a ligand capable of
forming bridge between the two complexes.
Cis- and trans- isomers of the complexes can be detected by Kurnakov’s test.
CFAE is equal to the difference between CFSE of reactant and intermediate.
Metal Complexes having low ( -ve) or zero value of CFAE are labile complexes.
Metal Complexes having high ( +ve) value of CFAE are inert complexes.
Weak field octahedral complexes of metal ions with d0,d1,d2,d4,d5,d6,d7,d9,d10 are
labile (-ve CFAE).
Strong field octahedral complexes of metal ions with d0,d1,d2,d7,d9 and d10
configuration are labile(-ve CFAE).
Strong field octahedral complexes of metal ions with d0,d1,d2,d7,d9 and d10
configuration have positive value of CFAE (inert complexes).
All non-transition metals complexes are labile in nature.
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Multiple Choice Questions
Q.1.
Q.2.
Q.3.
Q. 4
Q.5.
Q.6.
Q.7.
Which one of the following statement is incorrect?
(a) Most of the inorganic reactions are ionic.
(b) Reactions of transition metal complexes are slow.
(c) It is possible to study the mechanism of transition metal complexes.
(d) It is possible to study the mechanism of ionic reaction.
Which of the following statement is true for the following reaction?
x
+
y-z
x---y---z
x-y + z
(a) The energy of x---y---z is lowest.
(b) x---y---z is very stable.
(c) x---y---z has a long life.
(d) x---y---z cannot be isolated.
The reaction is an example of:
Hg+2
[Hg(NH3)5Cl]++
Co+2
[Co(NH3)5Cl]+ +
(a) Electrophilic substitution reaction.
(b) Nucleophilic substitution reaction.
(c) Electrophilic addition reaction.
(d) Nucleophilic addition reaction.
In the dissociative mechanism of octahedral complexes, the more stable intermediate
formed is
(a) Square planar
(b) Square pyramidal
(c) Prismatic
(d) Trigonal pyramidal
Which of the following statement is/are correct about SN1 mechanism of octahedral
complexes:
(i ) It is also known as dissociative mechanism.
(ii) It generally occurs through TBP intermediate.
(iii) It occurs in a single step.
(iv) The rate depends on the concentration of the reactant only.
(a). (i) only
(b) (i) & (iv)
(c) (ii) & (iii)
(d) (i),(ii),(iii) & (iv)
Which of the following conditions is favorable for SN1 mechanism?
(a) Smaller size of the metal ion.
(b) Higher charge on metal ion.
(c) Larger size of the leaving group.
(d) Absence of chelating group in the complexes.
Which of the following condition is favorable for SN2 mechanism?
(a) Large size of the metal ion.
(b) Lower charge on the metal ion.
(c) Larger size of the incoming group.
(c) Smaller size of the leaving group.
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Q.8.
Q.9.
Q.10.
Q.11.
Q.12.
Q.13.
Q.14.
Which of the following statements is/are true about SN1 reactions?
(i) In SN1 mechanism, the rate determining slowest step is metal-ligand bond breaking
step.
(ii ) In SN1 mechanism, the rate determining slowest step is metal-ligand bond making
step.
(iii) In SN1 mechanism the co-ordination no. of the complex is decreased from 6 to 5.
(iv) In SN2 mechanism the co-ordination no. of the complex is decreased from 6 to 5.
(a) (i) & (ii)
(b) (i) & (iii)
(c) (i),(ii) & (iii)
(d)(i),(ii) & (iv)
Mention the correct statement:
(a) In SN1 mechanism the rate, r = k[ML5X][Y]
(b) In SN2 mechanism the rate, r = k[ML5X]
(c) In SN1 mechanism the rate, r = k[ML5X]2
(d) In SN2 mechanism the rate, r = k[ML5X][Y]
Mention the correct statement about SN2 mechanism:
(a) It is also known as dissociative mechanism.
(b) In this mechanism the intermediate formed has co-ordination no. less than the
co-ordinationno. of initial complex.
(c) It is also known as inter ligand associative mechanism(Ia).
(d) In this mechanism pentagonal bi pyramidal (PBP) intermediate is formed, while
octahedral wedge intermediate is more common.
Mention the correct statement about inert and labile complexes:
(a) [Ni(CN)4]-2 is thermodynamically unstable but kinetically stable.
(b) [Co(NH3)6]-2 is thermodynamically stable but kinetically labile.
(c) Labile complexes are those in which ligand substitution takes place easily.
(d) The terms inert and labile are thermodynamic terms.
Mention the correct statement about complexes:
(a) Outer orbital complexes of Ni(II) are labile.
(b) Outer orbital complexes of Cr(III) are inert.
(c) Inner orbital complexes of Sc(III) are inert.
(d) Outer orbital complexes of Zn (II) are labile.
Mention the correct statement(a) Complexes having sp3d2 hybridization have strong bonds than the complexes having
d2sp3.
(b) Complexes having d2sp3 hybridization have strong bonds than the complexes having
sp3d2.
(c) Both have equal bond strength.
(d) It cannot be decided.
CFAE is also known as(a) The difference between CFSE of reactant and product.
(b) The difference between CFSE of reactant and intermediate.
(c) The difference between CFSE of product and intermediate.
(d) The CFSE of reactant only.
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Q.15. Mention the correct statement(i) Complexes having low( -ve) CFAE are labile.
(ii) Complexes having zero CFAE are labile.
(iii) Complexes having high (+ve) CFAE are inert.
(iv) Complexes having zero CFAE are inert.
(a) (iv) only
(b) (i) & (ii)
(c) (ii) & (iii)
(d) (i),(ii) & (iii)
Q.16. Mention the incorrect statement about SN1 reactions which are occurring through square
pyramidal intermediate(a) Weak field octahedral complexes of metal ions with d0,d1,d2,d4,d5,d6,d7,d9,d10 are
labile.
(b) Weak field octahedral complexes of metal ions with d3 or d8 configurations have
–ve CFAE.
(c) Strong field octahedral complexes of metal ions with d0,d1,d2,d7,d9 and d10
configuration are labile.
(d) Strong field octahedral complexes of metal ions with d0,d1,d2,d7,d9 and d10
configuration have negative value of CFAE.
Q.17. [Co(NH3)5X]+2
+
H2O
[Co(NH3)5(H2O)]+3 +
Xis an `example of(a) Acid hydrolysis
(b) Base hydrolysis
(c) Anation reaction
(d) None of these
+3
Q.18. [Co (NH3)5(H2O)]
+
X
[Co(NH3)5X]+2 + H2O
is an example of(a) Acid hydrolysis
(b) Base hydrolysis
(c) Anation reaction
(d) None of these
Q.19. [Co (NH3)5Cl]+2 +
OH
[Co(NH3)5(OH)]+2
+
Clthe above reaction follows(a) SN1 mechanism
(b) SN2 mechanism
(c) SN1CB mechanism
(d) SNi mechanism
Q.20 [Co (NH3)5Cl]+2
+
OH
[Co(NH3)5(OH)]+2
+
Cl(i) The rate of above reaction depends upon the concentration of nucleophile.
(ii) When the concentration of –OH is high it follows first order rate law.
(iii) It follows second order mechanism.
(iv) It involves two steps in its mechanism.
Which of the following statements is/are correct?
(a) (i) only
(b) (i) & (ii)
(c) (iii) & (iv)
(d) All are correct.
Q.21. Trans effect is explained by(a) Polarization theory
(b) Mulliken theory
(c) Pauling theory
(d) Magnetic theory
Q.22. With the increase in trans effect of ligands, the rate of reaction
(a) Decrease
(b) Increase
(c) Neither increase nor decrease
(d) May slightly increase or decrease.
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Q.23. [Co (NH3)5X]+2
+
H2O
[Co(NH3)5(H2O)]+3 +
XMention the correct statement about the above reaction(a) It is found to be of second order
(b) It is found to be of zero order.
(c) H2O is involved in rate determining step.
(d) H2O does not affect the rate of reaction.
Q.24. Trans effect is not shown by(a) [PtCl4]-2
(b) [Pt(NH3)3Cl]+1
(c) cis-[Pt(NH3)2Cl2]
(d) trans-[Pt(NH3)2Cl2]
Q.25. For aquation reaction, the favorable condition is(a) pH < 3
(b) pH < 7
(c) pH > 7
(d) pH > 12
Q.26. For inner sphere mechanism electron transfer reactions:
(a) both the complexes should be inert
(b) both the complexes should be labile
(c) one should be inert and other should be labile
(d) the rate of reaction decreases with increase in nucleophilic character of bridging
ligand.
Q.27. For outer sphere mechanism electron transfer reactions:
(a) Both the complexes should be inert.
(b) Both the complexes should be labile.
(c) One should be inert and other should be labile.
(d) Electron transfer is slow if the ligands are pi-acceptor.
Q.28. Mention the correct statement about inner sphere mechanism:
(a) The inert complex should have a ligand capable of forming bridge between the two
complex.
(b) The labile complex should have a bridging ligand.
(c) Both the complexes should have a bridging ligand.
(d) None of the complexes should have a bridging ligand.
Q.29. Mention the correct statement about electron transfer reactions:
(a) Electron transfer reaction occurring through inner sphere mechanism are faster than
outer sphere mechanism.
(b) Electron transfer reaction occurring through outer sphere mechanism are faster if
Ligands are pi- acceptor.
(c) Electron transfer reaction occuring through outer sphere mechanism are faster if the
conductivity of ligand is high.
(d) All are correct.
Q.30. The reaction of PtCl4-2 with two equivalents of NH3 produces:
(a) cis-Pt(NH3)2Cl2
(b) trans- cis-Pt(NH3)2Cl2
(c) both (a) & (b)
(d) cis-[Pt(NH3)2Cl4]-2
Q.31. The correct order of trans effect is
(a) H->SCN->Br->H2O
(b) CO> Py> H2O> CH3(c) C6H5-> I-< Py >-OH
(d) CO>H2O>CH3->Py
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Q.32. Which of the following is the theory of trans effect:
(a) Mulliken theory
(b) Huckel theory
(c) pi-bonding theory
(d) Sigma-bonding theory
Q.33. Electrostatic polarization theory was proposed by:
(a) Guldberg
(b) Einstein
(c) Gringberg
(d) Chatt
Q.34. Cis- and trans- isomers are detected by:
(a) Lucas test
(b) Kurnakov’s test
(c) Mulliken test
(d) Ring test
Q.35. Pi-bond in tetrahedral complexes is formed by the following symmetry;
(a) t1
(b) t2
(c) e
(d) None of these
Q.36. Which of the following metal orbital does not take part in sigma bonding?
(a) dxy
(b) dyz
(c) dzx
(d) dx2-y2, dz2
Q.37. Which of the following ligand orbital form pi-bond in octahedral complexes?
(b) dz2
(a) dx2-y2
(c) dxy , dyz , dzx
(d) None of these
Q.38. In an octahedral complex, non-bonding orbital’s are:
(a) 4s
(b) 4px , 4py , 4pz
(c) 3dx2-y2, 3dz2
(d) 3dxy , 3dyz , 3dzx
Q.39. MOT is also known as:
(a) VBT
(b) LFT
(c) CFT
(d) None of these
Q.40. The reactions of Ni(CO)4 with the ligands (L=PMe3 or P(OMe)3) yields Ni(CO)3L . The
reaction is
(a) Associative
(b) Dissociative
(c) Interchange (Ia)
(d) Interchange (Id)
Q.41. The platinum complex of NH3 and Cl ligands is an anti-tumour agent. The correct
isomeric formula of the complex and its precursor are
(a) cis-Pt(NH3)2Cl2 and PtCl4-2
(b) trans- (NH3)2Cl2 and PtCl4-2
(c) cis- Pt(NH3)2Cl2 and Pt(NH3)4+2
(d) trans- Pt(NH3)2Cl2 and Pt(NH3)4-2
Q.42. The order of reactivity of ligands NMe3, PMe3, and CO with complexes MeTiCl3 and
(CO)5Mo(Ph) are:
(a) CO > PMe3 > NMe3 and CO > NMe3> PMe3
(b) PMe3 > CO > NMe3 and NMe3> CO > PMe3
(c) NMe3> PMe3> CO and CO > PMe3 > NMe3
(d) NMe3> CO > PMe3 and PMe3 > NMe3> CO
Q.43. The reaction of PtCl4-2 with NH3 gives product A while its reaction with [NO2]-2 followed
by NH3 gives product B. The A and B respectively, are:
(a) trans- [Pt(NH3)2Cl2]and trans-[ Pt(NH3)Cl2(NO2)](b) cis-[Pt(NH3)2Cl2] and trans-[ Pt(NH3)Cl2(NO2)]-
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Q.44.
Q.45.
Q.46.
Q.47.
Q.48.
Q.49.
Q.50.
Q.51.
Q.52.
Q.53.
(c) cis-[Pt(NH3)2Cl2] and cis-[ Pt(NH3)Cl2(NO2)](d) trans- [Pt(NH3)2Cl2]and cis-[ Pt(NH3)Cl2(NO2)]Consider thr following reaction:
[Cr(H2O)6]+2 +
[CoCl(NH3)5]+2
[Co(NH3)5H2O]+2 + [CrCl(H2O)5]+2
[Fe(CN)6]-4 +
[Mo(CN)8]-3
[Fe(CN)6]-3 +
[Mo(CN)8]-4
Which one of the following is the correct statement?
(a) Both involve an inner sphere mechanism.
(b) Both involve an outer sphere mechanism.
(c) Reaction 1 follows an inner sphere and reaction 2 follows outer sphere mechanism.
(d) Reaction 1 follows an outer sphere and reaction 2 follows inner sphere mechanism.
Lability of the ions Cr+2, Mn+2 and V+2 should follow the order:
(a) Cr+2 > Mn+2 > V+2
(b) Mn+2 > Cr+2 > V+2
+2
+2
+2
(c) Mn > V > Cr
(d) V+2> Cr+2> Mn+2
The correct order of rate of exchange of water molecules between the co-ordination
sphere and bulk is:
(b) Cr+3< Al+3< Ni+2< Cr+2
(a) Cr+3 < Al+3 < Cr+2< Ni+2
(c) Cr+3 < Ni+2< Cr+2< Al+3
(d) Cr+3< Cr+2<Al+3< Ni+2
The Cr(III) species formed soon after electron transfer between IrCl6-2 and Cr(H2O)6+2 is:
(a) Cr(H2O)6+3
(b) Cr(H2O)5Cl+2
(c) CrCl6-3
(d) Cr(H2O)3Cl3
+2
+3
[Cr(H2O)6]
+
[CoCl(NH3)5]
[Co(NH3)5H2O]+2 + [CrCl(H2O)5]+3
The correct statement regarding the above reaction is that:
(a) It follows outer sphere mechanism
(b) It follows inner sphere mechanism with NH3 acting as the bridging ligand.
(c) It follows inner sphere mechanism with Cl- acting as the bridging ligand.
(d) It is not an electron transfer reaction.
In the inner sphere reduction of [CoCl(NH3)5]+2 with [Cr(H2O)6]+2 , the chloride:
(a) bridges the metal centre only.
(b) mediates electron transfer only.
(c) bridges and mediates electron transfer both.
(d) does not play any role.
CFSE of transition metal complexes can be determined by:
(a) UV-visible spectroscopy
(b) IR spectroscopy
(c) Microwave spectroscopy
(d) NMR spectroscopy
The substitutionally inert complex ion amongst the following is:
(a) [Cr(H2O)6]+3
(b) [Fe(H2O)6]+2
+2
(c) [Cr(H2O)6]
(d) [Ni(H2O)6]+2
The rate of exchange of cyanide ligands in the complexes
(i) [Ni(CN)4]-2
(ii) [Mn(CN)6]-3
(iii) [Cr(CN)6]-3
(a) (ii)>(i)>(iii)
(b) (iii)>(i)>(ii)
(c) (i)>(iii)>(ii)
(d) (i)>(ii)>(iii)
Electron transfer from [Fe(H2O)6]+2 to [Fe(H2O)6]+3 is likely to occur via:
(a) d-d transition
(b) inner sphere electron transfer
(c) SN1 mechanism
(d) Outer sphere mechanism
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Q.54. The
final
product
containing
chromium
in
the
reaction
between
+2
+2
+
[CoCl(NH3)5] ,[Cr(H2O)6] and H3O is:
(a) [Cr(NH3)(H2O)4Cl]+2
(b) [Cr(H2O)6]+3
+2
(c) [CrCl(NH3)5]
(d) [Cr(H2O)5Cl]+2
Q.55. The ability of a group to direct the entering ligand to occupy trans-position with respect
to the group is called:
(a) Steric effect
(b) Peroxide effect
(c) Inductive effect
(d) Trans effect
Q.56. Electron transfer is fast if:
(a) The electron belongs to t2g orbital
(b) The electron spins of the two complex ions are the same
(c) The concentration of the cations in the solution is high
(d) All of the above
Q.57. Electron transfer is fast if the conductivity of the ligand is:
(a) Zero
(b) Low
(c) High
(d) None of these
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Answers
1- (d),
2- (d),
3- (a),
4- (b),
5- (b),
6- (d),
7 - (a),
8 - (b),
9 - (d),
10 - (d),
11 - (c),
12 - (a),
13- (b),
14- (b),
15- (d),
16- (b),
17- (a),
18- (c),
19- (c),
20- (d),
21- (a),
22- (b),
23- (d),
24- (a),
25- (a),
26- (c),
27- (a),
28- (a),
29- (d),
30- (a),
,31-
(a),
32- (c),
33- (c),
34- (b),
35- (c),
36- (d),
37- (c),
38- (d),
39- (b),
40- (b),
41- (a),
42- (c),
43- (b),
44- (c),
45- (b),
46- (c,)
47- (a),
48- (c),
49- (c),
50- (a),
51- (a),
52- (a),
53- (d),
54 (d),
55- (d),
56- (d),
57- (c).
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Answers with Solution
(a)
(b)
45101117232930 ,313740-
4142-
434445464748495051-
52-
(d), Ionic reactions are very fast.
(d),
3- (a),
(b), Movement of less no. of bond takes place. Hence it is more stable.
(b) ,
6- (d),
7-(a),
8-(b),
9-(d),
(d), Movement of less no. of bond takes place. Hence it is more common.
(c),
12- (a),
13- (b),
14- (b),
15- (d),
16- (b),
(a),
18- (c),
19- (c),
20- (d),
21- (a),
22- (b),
(d),
24- (a),
25- (a),
26- (c),
27- (a),
28- (a),
(d),
(a), trans effect of Cl- > NH3
(a),
32- (c),
33- (c),
34- (b),
35- (c),
36-(d),
(c),
38- (d),
39- (b),
Ni(Co)4PMe3
(b),Ni(CO)4 -CO (slow) Ni(CO)3 + PMe3 (Fast)
Since rate does not depend upon the concentration of and nature of ligand
suggesting a dissociative mechanism.
(a), trans effect of Cl- > NH3. The precursor of this complex is PtCl4-2.
(c), In the first complex titanium is in highest oxidation state +4. So, react faster with
sigma – donor ligand. Whereas in the second complex Mo is in low oxidation
state. So, reactfaster with pi- acceptor ligands.
(b),
the order of trans effect is NH3 < Cl- < NO2- .
(c),
(b), We know that smaller the size ,lesser will be the liability of ion.
(c,) All non transition metal octahedral complexes are labile.
Rate of exchange of water is lowest in Cr+3 and Ni+2 .
(a), outer sphere mechanism.
(c), inner sphere mechanism or bridge mechanism.
(c), inner sphere mechanism or bridge mechanism.
(a), since electronic transitions occur in transition metal complexes in UV-VIS range
therefore CFSE can be determined by UV-VIS spectroscopy.
(a), Since both d3 and d8 configurations in weak field are inert but since [Cr(H2O)6]+3
is in higher oxidation state as compared to [Ni(H2O)6]+2 . Therefore [Cr(H2O)6]+3
will be substitutionally inert.
(a), Ni+2 (d8)
:
eg4 t2g4
=
Labile
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Mn+3(d4) LS :
t2g4eg0
=
Inert
3 0
+3
3
Cr (d )
:
t2g eg
=
Inert
53- (d),
54- (d), reaction proceed through inner sphere mechanism in Cl atom behaves as a
bridging ligand.
55- (d),
56-(d),
57-(c).
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Chapter 4
Metal π – Complexes (Carbonyls,Nitrosyls and Phosphines)
Critical Points:
1- Favorable conditions for a ligand to be pi-acceptor are availability of vacant
d-orbital, low oxidation state of metal and high electron density of metal.
2- CO, NO, CN- etc. behaves as σ-donor as well as π- acceptor ligand.
3- A metal cluster may be defined as a group of two or more metal atoms in which there
are substantial and direct bonds between the metal atoms.
4- Poly nuclear carbonyls, nitroyls and related compounds exist in lower oxidation
states.
5- In metal carbonyls metal generally exhibit zero oxidation state and metal carbonyls
are generally covalent in nature.
6- The tendency to retain cluster of metal atoms will predominate in those metals which
have large energies of atomization.
7- Among mononuclear carbonyl Fe(CO)5 is yellow and V(CO)6 is black.
8- Except Fe(CO)5 and V(CO)6 all other mononuclear carbonyls are colorless.
9- Fe2(CO)9 +
4Na
2Na2[Fe(CO)4] + CO
10- [IrCl(Ph3P)3] +
Cl2
[IrCl3(Ph3P)3
11- Co6(CO)16, Rh6(CO)16 and Ir6(CO)16 are paramagnetic in nature and do not follow 18
electron rule.
12- Fe(CO)5
U.V. Light
Fe2(CO)9 + CO
0
140 C
Fe + 5CO
13- Fe(CO)5
0
14- Fe(CO)5
70 C
Fe2(CO)9 + Fe3(CO)12
15- In Mn2(CO)10, Ru3(CO)12 and Os3(CO)12 all the CO groups are Terminal.
16- Polyhedral electron count ( PEC) = ( TVE - n × 12 ) /2
n
= no. of metal atoms.
TVE = total valence electron
n-1 = super hyper closo
n
= hyper closo
n + 1 = closo
n + 2 = nido
n + 3 = arachano
n + 4 = hypo
n + 5 = conjuncto
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17- In solid form Co2(CO)8 has two bridging CO groups. While in solution form it has no
bridging CO groups, solid form converts into liquid form by heating.
18- Linear NO is neutral and it donates 3 electrons, bent NO is also neutral but it donates
1 electron.
Ƞ3 - NO
linear
1
Ƞ - NO
bent
19- Ziegler-Nata Catalyst is Al(C2H5)3 + TiCl4.
20- Wilkinson’s Catalyst is [ RhCl(PPh3)3] and it contains 16 valance electrons.
21- Jahn Teller distortion will be large if eg is unsymmetrical however Jahn Teller
distortion will be small if t2g is unsymmetrical.
22- There will be no distortion if eg and t2g or both are symmetrical.
23- In trigonal bipyramidal complexes the two ligands lie on z- axis and there is xy plane
somewhere between the axis. In xy plane there are four electrons and on z-axis there
is only one electron in dz2 orbital:
dxz= dyz<dxy= d x – y <dz
24- Fe(CO)5+ 3NaOH
Na[HFe(CO)4] + Na2CO3 + H2O
25- V(CO)6 is paramagnetic due to the presence of unpaired electrons (17 electrons in
valance shell).
2
2
2
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Multiple Choice Questions
Q.1.
Q.2.
Q.3.
Q.4.
Q.5.
Q.6.
Q.7.
Q.8.
Q.9.
What are the favorable conditions for a ligand to be pi-acceptor?
(a) The ligand must have vacant orbital.
(b) The metal atom should be of low oxidation state.
(c) The electron density should be high on metal atom.
(d) All are correct.
Which is the correct statement about metal carbonyls?
(a) The C atom of CO molecule donates its electron pair to the metal atom.
(b) The O atom of CO molecule donates its electron pair to the metal atom.
(c) Both C and O atoms of CO molecule donate its electron pair to the metal atom.
(d) None of these.
Which of the following statement is incorrect about metal carbonyls?
(a) In metal carbonyls metal present in zero oxidation state.
(b) In metal carbonyls σ-bond as well as π-bond are formed between metal and carbon
atoms.
(c) In metal carbonyl CO act as a neutral ligand.
(d) Only σ-bond is formed between metal atom and carbon atom.
Which of the following is an example of poly nuclear carbonyl:
(a) Cr(CO)6
(b) Fe(CO)5
(c) W(CO)6
(d) Fe2(CO)9
The color of Fe(CO)5 is:
(a) White
(b) Black
(c) Yellow
(d) Brown
Which of the following is paramagnetic in nature?
(a)Cr(CO)6
(b)V(CO)6
(c)Fe(CO)5
(d)Ni(CO)4
Mention the incorrect statement about mononuclear carbonyls:
(a) These are readily soluble in organic solvent.
(b) These can be vaporized without decomposition.
(c) These carbonyls are more volatile than the others.
(d) They have specific color.
Mention the incorrect statement about poly nuclear carbonyls:
(a) They have the general formula Mx(CO)y.
(b) These are generally insoluble in organic solvent.
(c) They decompose at or below their melting point.
(d) These carbonyls are more volatile than the others.
Which of the following metal carbonyl cannot be formed by the direct combination
with CO?
(a) Cr(CO)6
(b)Mn2(CO)10
(c)Fe(CO)5
(d)Co2(CO)8
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Q.10. In the reaction,
4C6H5MgBr + CrCl3 + 2CO
A(unstable)
(H +)
Cr(CO)6 + 2Cr+3 + 12C6H5- + 3H2
The unstable intermediate formed is:
(b) Cr(CO)3(C6H5)3 (c) Cr(CO)4(C6H5)2 (d) Cr(CO)(C6H5)5
(a)Cr(CO)2(C6H5)4
Q.11. Which of the following compound has three bridging carbonyl group?
(a) Co2(CO)8
(b) Fe2(CO)9
(c) Mn2(CO)10
(d) None of these
Q.12. Which of the following has NOT three bridging carbonyl group?
(a) Fe2(CO)9
(b) Co4(CO)12
(c)Rh4(CO)12
(d) Fe3(CO)12
Q.13. In the given reactions,
(i)
(ii)
Q.14.
Q.!5.
Q.16.
Q.17.
Q.18.
OsO4
OsO4
+
+
5CO
9CO
250 ͦC , 350atm.
100 ͦC , 50atm.
?
?
the carbonyl formed in both the reactions are, respectively:
(a) Os(CO)5 in (i) &Os2(CO)9 in (ii)
(b) Os2(CO)9 in both
(c) Os(CO)5 in both
(d) Os2(CO)9 in (i) & Os(CO)5 in (ii)
Match the following:
List-1
List-2
(A)
Fe3(CO)12
1.
Tetrahedral
(B)
Ni(CO)4
2.
Octahedral
(C)
Fe(CO)5
3.
Trigonal Bipyramidal
+
(D)
[Ir(Ph3P)2(CO)(NO)Cl]
4.
Square Pyramidal
A
B
C
D
(a)
1
2
4
3
(b)
2
1
3
4
(c)
1
2
3
4
(d)
3
2
1
4
Which of the following oxidation state stabilizes the metal atom in carbonyl compounds?
(a) 1
(b) 2
(c) 3
(d) 0
The product of the following reaction is:
U.V. Light
Fe(CO)5
(a) Fe and CO
(b) Fe2(CO)9 and CO
(c) Fe3(CO)12
(d) None of the above.
Which of the following metal carbonyls is NOT found in liquid form at ordinary
temperature?
(a) Ni(CO)4
(b) Fe(CO)5
(c) Os(CO)5
(d)Mn2(CO)10
Consider the following statements about metal carbonyls:
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1- Generally mononuclear carbonyls are colorless while other is colored.
2- They are covalent in nature.
3- They are poor conductor of electricity.
4- They are generally paramagnetic in nature.
Which of the following statements given above is/are correct?
(a)
2 and 4
(b)
1 and 4
(c)
1,2 and 3
(d)
1,2,3 and 4
Q.19. The no. of bridging CO present in Ir4(CO)12 :
(a) 0
(b) 2
(c) 1
(d) 3
Q. 20. Which metal carbonyls do not obey 18- electron rule:
1- Co6(CO)16
2- Ir6(CO)16
3- Co4(CO)12
4- V(CO)6
(a)
3 and 4
(b)
2 and 3
(c)
1,2 and 4
(d)
1,2,3 and 4
Q.21. Match the followingCarbonyl Cluster
Total Valence Electron
1.
Rh6(CO)16
(A)
72
2.
Os5(CO)16
(B)
74
-2
3.
[Fe4C(CO)12]
(c)
86
4.
Os5(CO)15C
(D)
62
1
2
3
4
(a)
C
A
D
B
(b)
B
A
C
D
(c)
D
C
A
B
(d)
A
C
D
B
Q.22. An example of metal cluster with no bridging ligand:
(a) Mn2(CO)10
(b) Co2(CO)8
(c) Fe2(CO)9
(d) Fe3(CO)12
Q.23. The oxidation state of Mn in [Mn(NO)3(CO)] is:
(a) -1
(b) -2
(c) -3
(d) 0
Q.24. The compound formed by the reaction of NO and metals are called:
(a) Nitrite
(b) Nitrates
(c) Nitrosyls
(d) None of these.
Q.25. An aqueous solution of NaOH reacts with Fe(CO)5 to form:
(a)[HFe(CO)4](b) [HFe2(CO)4](c) [H2Fe(CO)4](d) None of these.
Q.26. Na in liq. NH3 reacts with Fe2(CO)9 to give:
(a) [Fe(CO)5]
(b) [HFe(CO)4](c) [H2Fe(CO)4](d) [Fe(CO)4]-2
Q.27. The HOMO in CO is:
(a) π-bonding
(b) σ-bonding
(c) π- antibonding
(d) σ-antibonding
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Q.28. The no. of metal-metal bonds in [(Ƞ5-C5H5)Fe(CO)2}2 :
(a) 0
(b) 1
(c) 2
(d) 3
Q.29. The no. of bridging and terminal CO groups in Co4(CO)12 is :
(a) 3 and 9
(b) 6 and 6
(c) 4 and 8
(d) 0 and 12
Q.30. Rh6(CO)16 has :
(a) all terminal CO groups.
(b) 10 terminal and 6 bridged CO groups.
(c) 4 bridged and 12 terminal CO groups. (d) 8 bridging and 8 terminal CO groups.
Q.31. Which of the following has lowest stretching frequency?
(b) Co(CO)4(c) Ni(CO)4
(d) Fe(CO)4-2
(a)V(CO)6+
Q.32. [Co(CO)4] is isolobal with:
(b) CH3
(c) CH2
(d) CH
(a) CH4
Q.33. In H2Ru6(CO)18 cluster, containing 8 co-ordinate Ru centres, the hydrogen atoms are:
(a) both terminal
(b) one terminal and other bridging
(c) both bridging between two Ru
(d) both bridging between three Ru
Q.34. Arrange the following in increasing order of CO stretching frequencies:
I. CO
II. Mo(CO)3(NH3)3
III. Mo(CO)6
IV. Mo(CO)3(PPh3)3
(a) IV < III < II< I
(b) III < IV < II< I
(c) II < III <IV<I
(d) I > II > III > IV
Q.35. Complex Mo(py)2(CO)4 has two forms. Which of the statement about these forms is
true?
(a) Cis- form will give single band around 2000 cm-1 in IR and Trans-form will give 4
bands.
(b) Cis- form will give 4 bands and Trans-form will give single band round 2000 cm-1 in
IR.
(c) Both Cis and Trans-form will give 4 bands.
(d) Both Cis and Trans-form will give single bands at 2000 cm-1 .
Q.36. Arrange the following in increasing order of CO stretching frequencies :
I. Cr(CO)6
II. [V(CO)6]III. [Mo(CO)6]+
IV. CO
(a) I > II > III > IV
(b) II < I < III < IV
(c) IV<I < II < III
(d) I < III < IV<II
Q.37. Carbonylate ions are formed by the action of
(a) Reaction of Lewis acid such as AlCl3 with CO and carbonyl halide.
(b) Reaction of Halogen with Fe(CO)5.
(c) Reaction of alkali with simple Carbonyl.
(d) By reduction of carbonyls with alkali metals.
Q.38. An example of species having quaderpole bond is :
(a) Mn2(CO)9
(b) Cr2O7-2
(c) [Re2Cl8]-2
(d) Hg2(CH3COO)2
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Q.39. Wilkinson’s catalyst is
(a) (Ph3P)3RhCl
(b) (Ph3P)RhCl
(c)Ph3P3RhCl
(d)(Ph3P)2RhCl2
Q.40. Waker’s process uses the catalyst:
(a) Wilkinson’s catalyst
(b) Ziese’s salt
(c) Ziegler’s-Nata catalyst
(d) Potash salt
Q.41. Which of the following statement is false about ferrocene?
(a) It obeys 18-electron rule.
(b) It is diamagnetic.
(c) It is an Orange solid.
(d) It resists electrophilic reaction.
Q.42. The neutral complex which follows 18- electron rule is:
(a) ( Ƞ5 – C5H5 )Fe(CO)2
(b) ( Ƞ5 – C5H5 )Mo (CO)3
Q.43.
Q.44.
Q.45.
Q.46.
Q.47.
Q.48.
(c) ( Ƞ5 – C5H5 )2Co
(d( Ƞ5 – C5H5 )Re( Ƞ6 – C6H6 )
The oxidative addition and reductive elimination steps are favored by:
(a) Electron rich metal centers.
(b) Electron deficient metal centers.
(c) Electron deficient and electron rich metal centers respectively.
(d) Electron rich and electron deficient metal centers respectively.
The square planar complex [IrCl(Ph3P)3] undergoes oxidative addition of Cl2 to give two
products:
(a) fac and mer
(b) cis and trans
(c) enantiomers
(d) linkage isomers
Solid Co2(CO)8 shows infrared CO stretching bands at 1857,1886, 2001, 2031, 2044,
2059, 2071 and 2112 cm-1. When dissolved in hexane, the carbonyl bands at 1887 and
1856 cm-1 disappears. These changes in infrared spectrum are due to:
(a) Loss of terminal CO
(b) Structural changes of Co2(CO)8involving conversion of terminal CO to bridging CO.
(c) Dissociation of Co2(CO)8toCo(CO)4.
(d) Structural changes of Co2(CO)8involving conversion of bridging CO to terminal CO.
Oxidation occurs very easily in case of:
(a) ( Ƞ5 – C5H5 )2Fe
(b) ( Ƞ5 – C5H5 )2Co
(c) ( Ƞ5 – C5H5 )2Ru
(d) ( Ƞ5 – C5H5 )2Co+
In Ziegler-Natta Catalysis the commonly used catalyst is:
(a) Al(C2H5)3 , TiCl4
(b) (Ƞ5 –Cp)2 TiCl2, Al(OH)3
(c) VO(acac)2 , Al2 (CH3)6
(d) TiCl4 , BF3
In the hydroformylation reaction, the intermediate CH3CH2CH2Co(CO)4:
(a) Forms an acyl intermediate CH3CH2CH2COCo(CO)4
(b) Forms an adduct with an olefin reactant.
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Q.49.
Q.50.
Q.51.
Q.52.
Q.53.
Q. 54.
Q.55.
Q.56.
Q.57.
(c) Reacts with H2 .
(d) Eliminates propane.
The no. of anti bonding electrons in NO and CO according to molecular orbital theory:
(a) 1 ,0
(b) 2 ,2
(c) 3 , 2
(d) 2 , 3
The correct combination of metal, number of CO ligands and charge for a metal carbonyl
complex [ M(CO)X ]-z that satisfies 18- electron rule is:
(a)M = Ti, x = 6, z = 1
(b) M = V, x = 6, z = 1
(c) M = Co, x = 4, z = 2
(d) M = Mo, x = 5, z = 1
The refluxing ofRhCl3.3H2O with an excess of PPh3 in ethanol gives a complex A.
Complex A and valence electron count on Rhodium are, respectively,
(a) [ RhCl(PPh3)3], 16
(b) [ RhCl(PPh3)5], 16
(c) [ RhCl(PPh3)3], 18
(d) [ RhCl(PPh3)5], 18
The binding modes of NO in 18 electron compound [Co(CO)3(NO)] and
[Ni(Ƞ5-Cp)(NO)], respectively, are
(a) Linear and bent (b) bent and linear
(c) linear and linear (d) bent and bent
Intense band generally observed for a carbonyl group in the IR spectrum is due to
(a) The force constant of CO bond is large.
(b) The force constant of CO bond is small.
(c) There is no change in dipole moment for CO bond stretching.
(d) The dipole moment changes due to CO bond stretching is large.
Total number of vertices in metal clusters [Ru6(C) (CO)17], [Os5(C) (CO)15] and
[Ru5(C)(CO)16] are 6, 5 and 5 respectively. The predicted structures of these
complexes respectively are:
(a) closo, nido and nido
(b) closo, nido and arachano
(c) arachano, closo and nido
(d) arachano, nido and closo
Reaction of Fe(CO)5 with OH leads to a complex A which on oxidation with MnO2 gives
B. Compound A and B respectively are:
(a) [HFe(CO)4]- and Fe3(CO)12
(b) [Fe(CO)5(OH)]-and Fe2(CO)9
(c) [Fe(CO)4]-2 and Mn2(CO)10
(d) [HFe(CO)4]-and Fe2O3
The no. of metal- metal bonds in dimmers [ CpFe(CO)(NO)]2 and [CpMo(CO)3]2
respectively are:
(a) 2 and 2
(b) 2 and 3
(c) 1 and 2
(d) 0 and 1
In the trans- PtCl2L(CO) complex, the CO stretching frequency for L = NH3,
pyridine, NMe3 decreases in the order:
(a) Pyridine > NH3 > NMe3
(b) NH3 > Pyridine > NMe3
(c) NMe3 > NH3 > Pyridine
(d) Pyridine > NMe3> NH3
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Q.58. The correct statement regarding terminal/ bridging CO groups in solid Co4(CO)12 and
Ir4(CO)12 is:
(a) Both have equal no. of bridging CO groups.
(b) Number of bridging CO groups in Co4(CO)12 is 4.
(c) The no. of terminal CO groups in Co4(CO)12 is 8.
(d) The no. bridging CO groups in Ir4(CO)12 is 0.
Q.59. On reducing Fe3(CO)12with an excess of Na, a carbonylate ion is formed. The Iron is
isoelectronic with:
(a) [ Mn(CO)5](b) [ Ni(CO)4]
(c) [Mn(CO)5](d) [V(CO)6]Q.60. For the reaction,
trans- [ IrCl(CO)(PPh3)2] + Cl2
trans- [ IrCl3(CO)(PPh3)2] ,
the correct observations:
(a) ʋCO(product) >ʋCO (reactant)
(b) ʋCO (product) < ʋCO (reactant)
(c) ʋCO (product) = ʋCO (reactant)
(d) ʋCO (product) = ʋCO (Free CO)
Q.61. The cluster having arachano type structure :
(a) [ Os3(CO)16]
(b)[ Os3(CO)12]
(c)[ Ir4(CO)12]
(d)[ Rh6(CO)16]
Q.62. The final product of the reaction [Mn(CO)6] + MeLi
is
+
(a)[Mn(CO)6] Me
(b)[Mn(CO)5Me]
(c)[Mn(CO)6]
(d)[(MeCO)Mn(CO)5]
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Answers
1-
(d),
2- (a),
3- (d),
4- (d),
5- (c),
6- (b),
7 - (d),
8 - (d),
9 - (b),
10 - (a),
11 - (b),
12 - (d),
13- (c),
14
(b),
15- (d),
16 (b),
17- (d),
18- (c),
19- (a),
20- (c),
21- (a),
22- (a),
23- (d),
24- (c),
25- (a),
26- (d),
27- (a),
28- (b),
29- (a),
30- (c),
31-(d),
32- (b),
33- (c),
34- (c),
35- (b),
36- (b),
37- (d),
38- (b),
39- (a),
40- (c),
41- (d),
42- (d),
43- (d),
44- (a),
45- (d),
46- (b),
47- (a),
48- (a),
49- (a),
50- (b),
51- (a),
52- (c),
53- (d),
54- (b),
55- (a),
56- (d),
57- (a),
58- (d),
59- (b),
60- (a),
61- (b),
62- (d)
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Answers with Solution
1- (d) [Favorable conditions for a ligand to be pi-acceptor are availability of vacant
d-orbital, low oxidation state of metal and high electron density of metal]
2- (a) [ CO behaves as σ-donor as well as π- acceptor ligand]
3- (d) [ In metal carbonyls metal generally exhibit zero oxidation state and metal carbonyls
are generally covalent in nature]
4- (d),
5- (c) [Fe(CO)5 is yellow and V(CO)6 is black]
6- (b) [V(CO)6 is paramagnetic due to the presence of unpaired electrons (17 electrons in
valance shell]
7- (d) [Except Fe(CO)5 and V(CO)6 all other mononuclear carbonyls are colorless]
8- (d)
9- (b) [Cr(CO)6, Fe(CO)5, Co2(CO)8and Ni(CO)4 can be formed by direct combination of
metal with CO]
10- (a)
11- (b) [ Fe2(CO)9, Co4(CO)12 and Rh4(CO)12 have three bridging carbonyl groups ]
12- (d)
13- (c) [ CO behaves as carbonylating as well as Reducing Agent in this reaction, Re2O7
reacts in the similar way with CO to form Re2(CO)9]
14 (b)
15- (d)
16 (b) [Fe(CO)5
U.V. Light
Fe2(CO)9 + CO ]
17- (d)
18-(c)
19-(a)
20- (c) [ Hexa nuclear carbonyls and V(CO)6 do not obey 18 electron rule & they are
paramagnetic in nature]
21- (a) Total Valence Electron
Rh6(CO)16
=
9 × 6 + 16 × 2
=
86
Os5(CO)16
=
8 × 5 + 16 × 2
=
72
-2
[Fe4C(CO)12]
=
8 × 4 + 4 × 1 + 12 × 2 + 2
=
62
Os5(CO)15C
=
8 × 5 + 15 × 2 + 4 × 1
=
74
22- (a) In Mn2(CO)10 all the CO groups are Terminal.
23- (d) [ NO is neutral in the complex and it donates 3 electrons]
24- (c)
25- (a) Fe(CO)5 + 3NaOH
Na[HFe(CO)4] + Na2CO3 + H2O
26- (d) Fe2(CO)9 +
4Na
2Na2[Fe(CO)4] + CO
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27- (a) CO molecule contains 14(6 + 8) electrons.
σ 1s2 σ* 1s2 σ 2s2 σ* 1s2 σ 2pz2 π2px2 π2py2
28- (b)
29- (a) [Co4(CO)12, Rh4(CO)12 and Fe2(CO)9 contain 3 bridging CO group]
30- (c)
31- (d) [ Since Fe has high electron density therefore π back bonding will be maximum and
C-O stretching will be low]
32- (b) [ Co(CO)4 requires 1 more electron to complete 18 electrons while CH3 also requires
only 1 electron to complete its octet. Therefore both of these are isolobal to each
other]
33- (c) [Both H atoms are present as triply bridged with three Ru centers ]
34- (c) CO groups in Mo(CO)6 are all terminal while NH3 is electron donor so supplies
electrons to Mo for back donation to π* orbital’s of CO, PH3 is a weak donor than
NH3.
35- (b) [ In trans form both the CO groups have same electronic environment therefore it
contains only single peak. While in cis form all the CO groups have different
chemical environment therefore it contains 4 different peaks in IR spectrum.]
36- (b) Positive charge on metal decreases back bonding , conversely, greater negative
Charge on metal increases back bonding. Thus, increases metal-carbon bond order.
So, C-O bond weakens resulting in the reduction in frequency.
[V(CO)6]1860cm-1
Cr(CO)6
2000cm-1
[Mo(CO)6]+ 2090 cm-1
CO
2143 cm-1
37- (d) Due to the formation of ammoniated electron.
38- (b) TVE
2 × 6 + 7 × (-2) + 2
= 28
No. of metal – metal bond = 36-28
`
= 8/2
= 4
39- (a)
40- (c)
41- (d) [ Electrophilic substitution can take easily on ferrocene. ]
42- (d) ( Ƞ5 – C5H5 )Re (Ƞ6– C5H5)
5 + 7 + 6 = 18
43- (d) [ oxidative addition means oxidation, i.e., loss of electron. It can occur only at
electron rich metal. While reductive elimination means reduction, i.e., gain of
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444546-
474849-
50-
51525354-
electrons. It can occur only at electron deficient metal atom, ]
(a) {[IrCl(Ph3P)3] + Cl2
[IrCl3(Ph3P)3 }
The product forms fac and mer isomers]
(d) [ In solid form Co2(CO)8 has two bridging CO groups. While in solution form it
has no bridging CO groups]
(b)
Compound
Number of electron in valance shell of central atom
5
( Ƞ – C5H5 )2Fe
18
5
19
( Ƞ – C5H5 )2Co
5
( Ƞ – C5H5 )2Ru
18
5
+
18
( Ƞ – C5H5 )2Co
(a) Ziegler-Nata Catalyst is Al(C2H5)3 + TiCl4
(a) In the hydroformylation reaction, the intermediate CH3CH2CH2Co(CO)4 gets
transformed to acyl intermediate CH3CH2CH2COCo(CO)3 .
(a) NO molecule contains 15(7 + 8) electrons.
σ 1s2 σ* 1s2 σ 2s2 σ* 1s2 σ 2pz2 π2px2 π2py2π* 2px1 (one valance electron in antibonding molecular orbital)
CO molecule contains 14(6 + 8) electrons.
σ 1s2 σ* 1s2 σ 2s2 σ* 1s2 σ 2pz2 π2px2 π2py2 (zero valance electron inantibonding molecular orbital)
(b) M = V,
x = 6,
z=1
-1
i.e. [ V(CO)6]
5 + 2 × 6 + 1 = 18
(a) [ Complex [ RhCl(PPh3)3] is Wilkinson’s Catalyst and it contains 16 valance
electrons]
(c) Ƞ3 – NO
linear
1
Ƞ - NO
bent
(d)
(b) Polyhedral electron count ( PEC) = ( TVE - n × 12 ) /2
n
= no. of metal atoms.
TVE = total valence electron
n-1 = super hyper closo
n
= hyper closo
n + 1 = closo
n + 2 = nido
n + 3 = arachano
n + 4 = hypo
n + 5 = conjuncto
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55- (a)
56- (d) Step-I :- Determine the total valence electron ( TVE ) = A
Step-II :- B = (n × 18 ) – A
Step-III:- B/2 gives the no. of metal – metal bonds in a compound.
57- (a)
58- (d)
59- (b) Fe3(CO)12
[Fe(CO)4]-2
8 + 8 + 2 = 18
-2
[Fe(CO)4] is isoelectronic with Ni(CO)4.
60- (a) ʋCO(product) >ʋCO (reactant), because in product Ir is present in +3 oxidation state
and in reactant it is present in +1 oxidation state.
61- (b)
62- (d) [Mn(CO)6] + MeLi
[(MeCO)Mn(CO)5] (migratory insertion)
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Chapter 5
Co-ordination Chemistry
(Structure, Bonding, Color, Magnetic Properties and Their Spectra)
Critical Points:
1- In haemoglobin iron is present in +2 oxidation state.
2- cis - [PtII (NH3)2Cl2] is used in chemotherapy in cancer.
3- Jahn Teller effect is the separation of the degenerate electronic states in a given
symmetry so as to remove degeneracy.
4- If t2g orbital is unsymmetrically filled than there is less Jahn-Teller distortion and
If eg orbital is unsymmetrically filled then Jahn-Teller distortion will be large.
However in case of symmetriclly filled orbitals there is no Jahn-Teller distortion.
e.g. in Cu+2 (d9 configuration) eg will be unsymmetrically filled. Hence large
distortion occurs in this complex.
5- Zieses salt has square planar geometry.
6- EDTA is an hexadentate ligand.
7- trans-[Pt(NH3)2Cl2] does not show optical isomerism because it is super- imposable on its
mirror image.
8- CO, NO, PPh3 are well known as π- acid ligands.
9- V(CO)6 does not obey EAN and 18-electron rule.
10- MnO4- involves ligand to metal charge transfer (LMCT).
11- Fe - Oxygen transport (Haemoglobin, haemocyanin) oxygen storage (myoglobin)
Mn- Oxidation of H2O2 to O2 (Photosynthesis II)
Mo- Nitrogen fixation (Nitrogenase)
ZnHydrolysis of peptide linkage (carboxy peptidase),
Decarboxylation of oxalo acetic acid (oxaloacetade carboxylase)
Oxidation of alcohol (alcohol dehydrogenase)
CuOxygen transport (Haemocyanin)
Electron transfer (Blue copper protein)
Dismutation of superoxide (Superoxide dismutase)
12- Tropylium exists in +1 oxidation sate.
13- In trisilyl amine three sp2 orbital’s are involved in σ bonding giving a plane trigonal
structure.
14- In general the π- accepting ability of phosphine increases as the electro-negativity of the
substituent increases.
15- Spin- orbit coupling of d- electron takes place when t2g orbitals are asymmetrically
filled.
16- In trigonal bipyramidal complexes the two ligands lie on z-axes and three in xyplane, somewhere in between the axes. In xy plane there are 4 electrons and on z-axes
there is only one electron in dz2 orbital.
dxz= dyz<dxy= d x – y <dz
2
2
2
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Multiple Choice Questions
Q.1.
Q.2.
Q.3.
Q.4.
Q.5.
Q.6.
Q.7.
Q.8.
Q.9.
The self-indicating silica gel (impregnated with cobalt chloride) turns pink on absorbing
moisture and becomes blue on heating. The pink and blue color is respectively due to
(a)
[Co(H2O)6]+2 and [CoCl4]-2
(b)
[Co(H2O)6]+2 and Co2O3
(c)
[Co(H2O)6]+2 and [Co(H2O)6]+3
(d)
Co+2 and Co+3
Hemoglobin, a complex containing iron, is a constituent of blood. The oxidation state of
iron in the complex is:
(a) 0
(b) +1
(c) +2
(d) +3
The complex compound used in the chemotherapy of cancer is:
(a) cis - [PtIV (NH3)4Cl2]Cl2
(b)cis - [PtIV (NH3)4Cl4]
(c) cis - [PtII (NH3)2Cl2]
(c) trans - [PtII (NH3)4Cl2]
CrO3 is bright in color due to:
(a) d-d transition
(b) CT transition
(c) both (a) and (b) (d) None of these
The experimental magnetic moment of K3[Fe(CN)6] is 2.3 µ B and is attributed to the:
(a) Spin only value of low spin Fe
(b) Spin only value of high spin Fe
(c) Low spin Fe with orbital contribution.
(d) High spin Fe with orbital contribution.
Coordinated water molecules of Cd(II) complex can be successively replaced by Brfinally to result in [CdBr4]-2. In this process the fourth equilibrium constant is observed
and be higher than one because :
(a) Equilibrium for the last step is always the highest.
(b) Three molecules of water are released during the fourth step.
(c) The aqua-Cd(II) species is octahedral.
(d) The Br- anion replaces a neutral H2O molecule from the coordination sphere.
John-Teller effect is not observed in the high spin complexes of:
(a) d4
(b)d7
(c)d8
(d)d9
The d- orbital will split under trigonal bipyramidal ligand field into:
(a) One level
(b) Two level
(c) Three level
(d) Four level
Which of the following acts as a π-acid ligand?
(a) F(b) O-2
(c) CO
(d)NH3
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Q.10. The no. of absorption band observed in [FeF6]-3 and[CoF6]-3 respectively are,
(a) 1 and 3
(b) 0 and 1
(c) 0 and 3
(d) 3 and 1
-2
-2
-2
Q.11. [NiX4] , [CoX4] and [MnX4] where X is a halogen:
(a) Colored
(b) Colored due to L
MCT
(c) Colorless
(d) Colored due to M
LCT
Q.12. Purple color of iodine vapour is due to:
(a) d-d transition
(b) π -σ* transition
(c) C-T transition
(d) π* -σ* transition
Q.13. The Chromium (III) species soon after the electron transfer between IrCl6-2 and
[Cr(H2O)6]+2 is:
(a) [Cr(H2O)6]+3
(b) [Cr(H2O)5Cl]+2
(c) [CrCl6]-3
(d) [Cr(H2O)3Cl3]
n
Q.14. Which of following metal fragments d - MLmis isolobal with CH?
(a) d7- ML5
(b) d9- ML3
(c) d8- ML4
(d) d5- ML6
Q.15. The complex which exhibits lowest energy electronic absorption band is :
(a) [NiCl4]-2
(b) [Ni(H2O)6]+2
(c) [Ni(CN)4]-2
(d) [NiCO)4]
Q.16. Jahn-Teller distortion affects the geometry of
(b) [MnCl4]-2
(a) [Cu(NH3)4]+2
(c) [Ni(NH3)4]+2
(d) None of these
Q.17. The purple color of KMnO4 is due to the transition:
(a) CT (L
M)
(b) CT (M
L)
(c) p-d transition
(d) d-d transition
Q.18. The asymmetric nature of visible absorption band of [Ti(H2O)6]+2 is due to:
(a) Laprote’s allowed transition
(b) Laprote’s forbidden transition
(c) Dynamic Jahn-Teller
(d) Intensity stealing transition
Q.19. Which of the following has zero field stabilization energy in octahedral complexes?
(a) Fe+3 (low spin)
(b) Fe+3 (high spin)
(c) Cr+3 (high spin)
(d) Co+2 (low spin)
Q.20. For the metal olefin complex [PtCl3(C2H4)]- and [PtCl3(C2F4)]- the correct statement is :
(a) C-C bond length is same in both (i) and (ii)
(b) C-C bond length in (i) is smaller than (ii)
(c) C-C bond length in (i) is larger compared to that of (ii)
(d) a metallocycle is formed in each complex.
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Q.21. In trigonal bipyramidal crystal field, the d- orbital with the highest energy is :
(a) dxy
(b) dyz
(d) dz2
(c) dx2-y2
Q.22. In TeCl4, the central atom tellurium involves
(a) sp3 hybridisation
(b) sp3d hybridisation
(c) sp3d2 hybridisation
(d)sp3d3 hybridisation
Q.23. Jahn-Teller effect is in the field of:
(a) Nuclear Physics
(b) Vibronic interaction
(c) Thermodynamics
(d) Kinetic theory of gases
Q.24. Ziese’s salt is:
(b) K2[PtCl3- Ƞ-C3H6]
(a) K+[PtCl3(C2H4)]+
2
(c) K [PtCl3- Ƞ -C2H4]
(d) K+[PtCl3- Ƞ2-C3H6]ClQ.25. The complexes [Co(NH3)3NO2]Cl2 and [Co (NH3)5(ONO)]Cl2 are example of
(a) Linkage isomers
(b) Ionization isomers
(c) Geometrical isomers
(d) Co-ordination isomers
Q.26. Among the following complexes , optical activity is possible in:
(a) [Co(en)(NH3)2Cl2]
(b) [Co (NH3)3(NO2)Cl]+
(c) [Co(CN)5NC](d) [Co(H2O)4Cl2]+
Q.27. Jahn-Teller effect is not observed in high spin complexes of.
(a) d4
(b) d7
(c) d8
(d) d9
Q.28. Which of the following is a hexadentate ligand?
(a) Acetyl Acetonato
(b) 1,10 phenanthroline
(c) Ethylene Diamine
(d) Ethylene diamine tetraacetic acid
Q.29. The Optical isomerism is not shown by the complexes:
(a) [Cr(ox)3]-3
(b) [Co(EDTA)](c) [Co(en)(NH3)2Cl2]
(d) trans-[Pt(NH3)4Cl2]
Q.30. “ Any non-linear molecular system in a degenerate electronic state will undergo some
kind of distortion which will lower its symmetry, thereby removing degeneracy ”.
This statement is:
(a) Crystal field effect
(b) Jahn-Teller effect
(c) Ligand- field effect
(d) Tetrahedral distortion effect
Q.31. The lowest energy d-d transition in Cr (+3) complexes varies in the order:
(a) CrCl-6 < Cr(H2O)6+3 < Cr(en)3+3 < Cr(CN)6-3
(b) CrCl-6 < Cr(en)3+3 < Cr(H2O)6+3 < Cr(CN)6-3
(c) Cr(CN)6-3<CrCl-6 < Cr(H2O)6+3 < Cr(en)3+3
(d) Cr(H2O)6+3 < Cr(en)3+3 < CrCl-6 <Cr(CN)6-3
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Q.32. Among the complexes K4[Cr(CN)6] (A),K4[Fe(CN)6] (B) , K3[Co(CN)6] (C) ,
K4[Mn(CN)6] (D), Jahn-Teller distortion is shown by
(a) A,B and C
(b) B,C and D
(c) A and D
(d) B and C
Q.33. Match the action of H2O2 in aqueous medium given in column A with the
oxidation/reduction listed in column B
Q.34.
Q.35.
Q.36.
Q.37.
A: action of H2O2
B: type of reaction
I: Oxidation in acid
(A) [Fe(CN)6]-3
[Fe(CN)6]-4
II: Oxidation in base
(B) [Fe(CN)6]-4
[Fe(CN)6]-3
III:Reduction in acid
(C) MnO4-
Mn+2
IV: Reduction in base
(D) Mn+4
Mn+2
The correct answer is :
(a) I - (A), II - (B), III - (C), IV - (D)
(b) I - (B), II - (D), III - (C), IV - (A)
(c) I - (C), II - (B), III - (D), IV - (A)
(d) I - (D), II - (A), III - (C), IV - (B)
What is the IUPAC name of [Co(NH3)3(NO2)Cl(CN)] compound?
(a) Chloro cyano nitro triamine cobalt (III)
(b) Triamine chloro cyano nitro cobalt (III)
(c) Cyano chloro nitro triamine cobalt (III)
(d) Nitro chloro cyano triamine cobalt (III)
The complex [Fe(phen)2(NCS)2] (phen = 1,10 phenanthroline) shows spin cross-over
behavior. CFSE and µ eff at 250 and 150 K , respectively are:
(a) 0.4 Δo, 4.90 BM and 2.4 Δo, 0.00 BM
(b) 2.4 Δo, 2.90 BM and 0.4 Δo, 1.77 BM
(c) 2.4 Δo, 0.00 BM and 0.4 Δo, 4.90 BM
(d) 1.2 Δo, 4.90 BM and 2.4 Δo, 0.00 BM
Which of the following does not obey EAN rule?
(a) Fe(CO)5
(b) V(CO)6
(c) K4[Fe(CN)6]
(d) Mn2(CO)10
The oxidation state of iron in met- haemoglobin is:
(a) +3
(b) +2
(c) +4
(d) 0
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Q.38. The correct d- electron configuration showing spin-orbit coupling is:
(a) t2g4 eg2
(b)t2g6 eg0
(c) t2g4 eg0
(d)t2g3 eg2
Q.39. Among the following the strongest oxidizing agent is:
(a) [WO4]-2
(b)[CrO4]-2
-2
(c) [MoO4]
(d)[ReO4]-1
Q.40. The no. of spin-allowed ligand field transitions for Ni(II) complexes with 3A2g ground
state are:
(a) 2
(b) 3
(c) 1
(d) 4
+2
Q.41. The light pink color of [Co(H2O)6] and the deep blue color of [CoCl4]-2 are due to:
(a) MLCT transition in first and d-d transition in second.
(b) LMCT transition in both.
(c) d-d transition in both.
(d) d-d transition in first and MLCT transition in second.
Q.42. In [Mo2(S2)6]-2 cluster the no. of bridging S2-2 and coordination no. of Mo respectively
are:
(a) 2 and 8
(b) 2 and 6
(c) 1 and 8
(d) 1 and 6
Q.43. The no. of possible isomers of [Ru(PPh3)2(acac)2] (acac = acetylacetone) is:
(a) 2
(b) 3
(c) 4
(d) 5
Q.44. The total no. of Cu-O bond present in the crystalline copper(II) acetate monohydrate:
(a) 10
(b) 6
(c) 8
(d) 4
Q.45. The substitution of – Cp group with nitric oxide is the easiest for:
(a) Ƞ2 – Cp2Fe
(b) Ƞ2 - Cp2CoCl
(c) Ƞ2 -Cp2Ni
(d) Ƞ2 – Cp2Co
Q.46. The molecule
OCH3
(CO)5M
C
Ph
Obey 18-electron rule. The two ‘M’ satisfying the condition are:
(a) Cr, Re+
(b) Mo, V
+
(c) V, Re
(d) Cr, V
Q.47. The correct spinel structure of Co3O4 is:
(a) (Co+2)t (2Co+3)octO4
(b)(Co+2)t (2Co+3 Co+3)octO4
(c)(Co+2 Co+3)t (Co+3)octO4
(d)(2Co+3)t (Co+2)octO4
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Q.48. In the solid state the CuCl5-3 ion has two types of bonds. These are
(a) Three long and two short
(b) Two long and three short
(c) One long and four short
(d) Four long and one short.
Q.49. The electronic transition is responsible for the color of the transition metal ion is:
(a) dπ- dσ
(b) dπ- dσ*
(c) dπ- dπ*
(d) dσ- dπ*
Q.50. The no. metal-metal bonds in [W2(OPh)6] is:
(a) 1
(b) 2
(c) 3
(d) 4
7
Q.51. The oxidation state of molybdenum in [(Ƞ - tropylium)Mo(CO)3]+ is :
(a) +2
(b) +1
(c) 0
(d) -1
Q.52. The Mulliken symbols for the spectroscopic states arising from the free-ion term F are:
(a) T2g + Eg
(b) T1g + T2g + T1u
(c) T1g + T2g + A2g
(d) T1g + A1g +T2g
-2
Q.53. Silica gel contains [CoCl4] as an indicator. When activated silica gel becomes dark blue
while upon absorption of moisture, its color changes to pale pink. This is because:
(a) Co(II) changes its coordination from tetrahedral to octahedral.
(b) Co(II) changes its oxidation state to Co(III).
(c) tetrahedral crystal field splitting is NOT equal to octahedral field splitting.
(d) Co(II) forms kinetically labile CO(III) forms kinetically inert complexes.
Q.54. The bands in the electronic spectrum of [Cr(NH3)6]+3 are due to the following transition:
4
4
2
(A) 4A2g
T1g
(B)4A2g
T2g
(C)4A2g
Eg
Identify the correct statement about them:
(a) Intensity of A is lowest
(b) Intensity of C is lowest
(c) Intensities of A,B and C are similar
(d) Intensities of B and C are similar.
Q.55. The no. of possible isomers for [Ru(bpy)2Cl2] is (bpy = 2,2’-bipyridine)
(a) 2
(b) 3
(c) 4
(d) 5
Q.56. Complex in which organic ligand is having only σ- bond with metal is:
(a) W(CH3)
(b) (Ƞ5 – C5H5)2Fe
(c) K[PtCl3(C2H4)
(d) (Ƞ6 – C6H6)2Ru
Q.57. [Ni(CN)4]-2 and [NiCl4]-2 complex ions are:
(a) Both diamagnetic.
(b) Both paramagnetic.
(c) Diamagnetic and paramagnetic respectively.
(d) Anti-ferromagnetic and diamagnetic respectively.
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Q.58. According to crystal field theory,Ni+2can have two unpaired electrons in:
(a) Octahedral geometry only
(b) Square-planar geometry only
(c) Tetrahedralgeometry only
(d) Both octahedral and tertrahedral geometries
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Answers
1-
(a),
2- (c),
3- (c),
4- (b),
5- (c),
6- (b),
7 - (c),
8 - (c),
9 - (c),
10 - (b),
11 – (b),
12 - (d),
13- (a),
14
(b),
15- (c),
16 (a),
17- (a),
18- (b),
19- (b),
20- (a),
21- (d),
22- (b),
23- (b),
24- (c),
25- (a),
26- (a),
27- (c),
28- (d),
29- (d),
30- (b),
31- (a),
32- (c),
33- (c),
34- (a),
35- (a),
36- (b),
37- (a),
38- (c),
39- (b),
40- (b),
41- (c),
42- (a),
43- (b),
44- (a),
45- (c),
46- (a),
47- (a),
48- (b),
49- (a),
50- (c),
51- (c),
52- (c),
53- (a),
54- (b),
55- (b),
56- (a),
57- (c).
58- (d),
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Answers with Solution
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(a) [Co(H2O)6]+2 is pink in color and [CoCl4]-2 is blue in color.]
(c) In haemoglobin iron is present in +2 oxidation state.
(c) cis - [PtII (NH3)2Cl2] is used in chemotherapy in cancer.
(b) Because Cr is present in highest oxidation state.
(c) [ According to spin only magnetic moment the value should be 1.73 µB but the
higher value (2.34 µB) is due to orbital contribution ( spin plus orbital magnetic
moment)]
(b)
(c) [If t2g orbital is unsymmetrically filled then there is less Jahn-Teller distortion and if
egorbital is unsymmetrically filled then Jahn-Teller distortion will be large.
However in case of symmetrically filled orbitals there is no Jahn-Teller distortion].
(c) [dxz= dyz< dxy = d x – y <d z ]
(c) CO, NO, PPh3 are known as π- acid ligands.
(b) [ Due to d5 and d6 configuration of Fe(III) and Co(III) ions respectively]
(b)
(d)
(a) [It follows outer sphere mechanism in which only oxidation state of central metal ion
changes and ligands remain same]
(b) d9- ML3 requires 3 electron to complete 18 electrons in its valance shell while CH
also requires 3 electron to complete its octet. So these are isolobal to each other.
(c)
(a) In Cu+2 (d9 configuration) eg will be unsymmetrically filled. Hence large distortion
occurs in this complex.
(a) Mn is present in +7 oxidation state. Hence L
M charge transfer takes place.
(b) In this complex Ti is present in +2 oxidation state, i.e. , d2 configuration. Hence d-d
transition takes place which ‘spin allowed’ but ‘Laprote fobidden’.
(b) Fe+3 (d5) [High spin] , i.e. , t2g3 eg2. Hence CFSE will be zero.
(a)
(d)
(b)
(b) [ Jahn Teller effect is the separation of the degenerate electronic states in a given
symmetry so as to remove degeneracy]
(c) [Zieses salt has square planar geometry]
(a) Because NO2 is an ambident ligand.
(a)
(c) t2g6 eg2 - No distortion.
(d) EDTA is an hexadentate ligand. And it forms 5 rings with the metal.
(d) trans-[Pt(NH3)2Cl2] does not show optical isomerism because it is super-imposable
on its mirror image.
2
2
2
FUNDAMENTAL CONCEPT OF TRANSITION AND INNER-TRANSITION ELEMENTS
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(b)
(a)
(c) t2g is asymmetrically filled. Hence weak distortion takes place.
(c)
(a)
(a)
(b) V(CO)6 does not obey EAN rule.
23 + 12 = 35
(a)
(c) Spin- orbit coupling of d- electron takes place when t2g orbitals are unsymmetrically
filled.
(b) In [WO4]-2 ,[CrO4]-2, [MoO4]-2and [ReO4]-1 all the metals have same oxidation state
but Cr has smallest size. Therefore it has strongest tendency to attract electron.
Therefore it is strongest oxidizing agent.
(b) Ni+2 has d8 configuration. So it has the term symbol 3F and 3P. In octahedral field 3F
splits into 3A2g , 3T2g and 3T1g terms but 3P does not split, it transform into 3T1g (P).So
three electronic transitions are
3
3
A2g
T2g (F)
3
3
A2g
T1g (F)
3
3
A2g
T1g (P)
(c) In both the compounds Co is present in +2 oxidation state, H2O & Cl- are weak
ligands. Hence d-d transition takes place in both the complexes.
(a)
(b)
(a)
(c)
(a)
(a) Co3O4 is a normal spinel compound. In normal spinel the Co+2 ions occupy
tetrahedral void andCo+3 ion occupy octahedral void. Therefore spinel structure of
Co3O4 is(Co+2)t (2Co+3)oO4.
(b) In trigonal bipyramidal complexes the two ligands lie on z-axes and three in
xy- plane, somewhere in between the axes. In xy plane there are 4 electrons and on z
axes there is only one electron in dz2 orbital.
(a) The electronic transition responsible for the color of the transition metal ion is dπ- dσ
which is according to LFT.
(c)
(c) Tropylium exists in +1 oxidation state. Hence oxidation state of Mo is 0.
(c)
(a)
(b) Since it is spin forbidden.
(b) [Ru(bpy)2Cl2] has two geometrical isomers( cis and trans ) trans form is optically
inactive while cis form is optically active. So [Ru(bpy)2Cl2] has three isomers]
FUNDAMENTAL CONCEPT OF TRANSITION AND INNER-TRANSITION ELEMENTS
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(a)
(c)
(d)
Compound
Hybridization of Ni+2
Number of unpaired electrons
[Ni(CN)4]-2
[NiCl4]-2
dsp2
sp3
0 (diamagnetic)
2 (paramagnetic)
Ni+2 = [Ar] 3d8, 4s0
Geometry
Octahedral
Possible Hybridization
Number of unpaired electrons
3 2
sp d
2
2
0
Square-Planar
dsp
Tetrahedral
sp3
2
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