Download coordination compounds - Ahlcon Public School , Mayur Vihar Ph

AHLCON PUBLIC SCHOOL, MAYUR VIHAR – I, DELHI – 110091.
CHEMISTRY- XII (2016 – 2017)
Assignment No: 1
COORDINATION COMPOUNDS
1.
Describe a simple test that will allow you to distinguish between the compounds:
[Co(NH3)5Br]SO4 and [Co (NH3)5SO4]Br.
2.
One mole of aqueous solution of the complex CoCl35H2O when treated with excess of
aqueous AgNo3 solution gave one mole of white ppt of Agcl. What is the complex.
3.
On the basis of the data given below, predict which of the two participating ligands is
stronger.
Cd2+ + 4NH3
[Cd(NH3)4]2+
K = 1.3 x 107
Cd2+ + 4CN[Cd(CN)4]2K = 7.1 x 108
4.
Which complex compound is used in chemotherapy?
5.
Using IUPAC norms, write the formulae for the following:
a) Potassium diaquabis (oxalato) chromate (III) trihydrate
b) trichloridopyridine chromium (III)
c) Potassium hexacyanomanganate(II)
d) Pentamminechlorido Cobald (III) chloride
e) Ceasiumtetrachlorido ferrate (III)
f) Potassium trioxalatoaluminate (III)
6.
How does EDTA help as a cure for lead poisoning?
7.
Combination between Pt (IV), NH3 and cl- results in the formation of seven complexes. One
these complexes is [Pt (NH3)6]Cl4.
a) Write the formulae and IUPAC names of other six complexes.
b) Which will have highest molar conductivity?
c) Which of these is non-ionic?
d) What is the C.N of Pt in these complexes?
8.
Write all the geometrical isomers of [Pt(NH3)(Cl2) (Py)Br] and show how many of these will
exhibit optical isomerism.
9.
Name the following coordination compounds using IUPAC System.
i) [Mn(H2O)6]SO4
ii) K3[Al(C2O4)3]
iii) [Co(NH3)5NO2]Cl2
iv) [PtBrCl (NO2)NH3]-
v) [PtCl(NH2CH3) (NH3)2]Cl
vi) Hg[Co(SCN)4]
vii) [CoCl2(en)2]Cl
viii) K3[Cr(C2O4)3]
ix) [CoCl(NO2)(NH3)4]Cl
x) [Cr(H2O)4Cl2]NO3
xi) [CO(NH3)4Cl (NO2)]NO3
xii) K[Pt(NH3)Cl3]
xiii) (C6H5)3
xiv) [Pt(Py)4] [PtCl4]
xv) [CO(en)2Cl (ONO)]+
xvi) [Cr(en)3]Cl3.
xvii) K3[Fe(C2O4)3]
xviii) K2[Cu(CN)4]
xix) [CoCl(NO2) (en)2]+
xx) Dextra K3[Ir(C2O4)3]
xxi) [(NH3)5Cr – OH – Cr (NH3)5]Cl5
xxii) [Cr(PPh3) (CO)5]
xxiii) Fe4[Fe(CN)6]3
xxv) [Co(NH3)5 (CO3)]Cl
xxvi) (en)2Co
xxvii) [Cr(NH3)5 (NCS)] [ZnCl4]
xxiv) [Pt(NH3)4]Cl2 [PtCl4]
Co(en)2 (NO3)2
xxviii) Mn3(CO)12
xxx) [{C6H5)3P}3Rh]Cl
xxxi) [VO(acac)2]
xxxiii) Fe(C5H5)2]
xxxiv) K2[OsCl5W]
xxix) [PtCl2(C5H5N) NH3]
xxxii) K2{PdCl4]
xxxv) [CoCl2(NH3)4]3[Cr(CN)6]
xxxvi) [PtCl2[(NH3)4] [PtCl2] xxxvii) Na[Co(CO)4]
xxxviii) [CoCl2(en)2]2SO4
xxxix) [Ni(dmg)2]
XL) [Ni(CO)4]
XLI) K[Ag(CN)2]
XLII) [Pt(NH3)4] [PtCl4]
XLIII)[CoBr2(en)2]Cl
XLIV) K4[Ni(CN)4]
XLV) Na[Au(CN)2]
XLVI) [Ni(H2O)2 (NH3)4]SO4
XLVIII) [CuBr4]2-
XLIX) K2[Pd Cl4]
XLVII) [Cu(H2O)2(NH3)4] SO4
10.
Why chelated complex are more stable than unchelated complex?
11.
Tetrahedral complexes do not show geometrical isomerism. Why?
12.
Explain each of the following observation:
a) Tetrahedral Ni(II) complexes are paramagnetic but squareplanar Ni(II) complexes are
diamagnetic
b) Only transition metals are known to form  - complexes.
13.
Draw a figure to show splitting of degenerate-d- orbitals in an octahedral crystal field. How
does the magnitude of o decide the actual configuration of d-orbitals in a complex entity?
14.
Which type of isomerism is shown by the following pairs:
i) [Co(NH3)4 (NO2) (Cl)]Cl and [Co(NH3)4Cl2]NO2
ii) [Co(NH3)4(CN2)] [Cr(NH3)2(CN)4] and [Co(NH3)5(CN)][Cr(NH3)(CN5)
iii) [Mn(CO)5(SCN)] and [Mn(CO)5 (NCS)]
iv) [Pt(NH3)4] [PtCl6] and [Pt(NH3)4Cl2] [PtCl4]
15.
Copper sulphate solution on mixing with ammonia (ratio 1:4) does not give test for Cu2+ ions
but give test for sulphate ions.
16.
In a complex ion [Co(NH3)3 (H2O)2Cl]+
a) Identify the ligand’s formula and charge on each one of them
b) Write the geometry of complex ion.
17.
write the formulae of the following coordination compounds:1) tetraamineaquachoridocobalt(III) chloride
2) potassium tetrahydrozincate(II)
3) sodium pentacyanonitrosyl / sulphidoferrate (III)
4) bis (acetylacetonato) / oxovanadium (IV)
5) sodium ethylene diaminetetraacetato chromate (II)
6) bis(dimethyl glyoximato)nickel(II)
7) sodium tetrafluorido oxochromate(IV)
18.
Arrange the following complexes in order of increasing electrical conductivity.
[CO (NH3)3Cl2] , [CO(NH3)5Cl]Cl2 , [CO(NH3)6]Cl3 , [CO(NH3)4Cl2]Cl.
19.
Name the metal present in
i) Chlorlophyll
ii) Haemoglobin
iii) Vitamin B12
iv) Cis-platin
20.
A metal ion Mn+ having d4 valence electronic configuration combines with 3 didentate ligands
to form a complex compound. Assuming o > p.
i) draw the diagram showing d orbital splitting during this complex formation
ii) Write the electronic configuration of the valence electrons of the metal Mn+ ion in terms of
t2g and eg.
iii) What type of hybridization will Mn+ion have?
iv) Name the type of isomerism exhibited by this complex
21.
Give the electronic configuration of the :a) d-orbitals of Ti in [Ti(H2O)6]3+ion in an octahedral crystal field.
b) Why is this complex coloured? Explain on the basis of distribution of electrons in the dorbitals:
c) How does the colour change on heating (Ti(H2O)6]3+ ion?
22.
Give the formula of each of the following coordination entities.
a) CO3+ ion is bound to one Cl-, one NH3 molecule and two bidentate ethylene diamine
molecules.
b) Ni2+ ion is bound to two water molecules and two oxalate ions.
CBSE – 2011
Write the name and magnetic behavior of each of the above coordination entities.
(At. No CO – 27 Ni – 28)
CBSE – 2011
23. A complex of the type [ M  AA2 X 2 ]n  is known to be optically active. What does this
indicate about the structure of the complex? Give one example of such complex.
24. Giving suitable example describe the importance of the formation of complex compounds in
the extraction of a particular metal from its natural source.
25. Mention applications of coordination com pounds in following areas giving an example of
each.
a) Analytical chemistry
b) Extraction of metals.
26. For the complex [ Feen2 Cl2 ]Cl , identify the following:
a)
b)
c)
d)
e)
f)
O.N of Fe
Hybrid orbitals and shape of the complex
Magnetic behavior of the complex.
Number of its geometrical isomers
Whether there may be optical isomer also.
Name of the complex.
27. Give the electronic configuration of the
a) d – orbitals of Ti in TiH 2O6  ion in an octahedral crystal field.
b) Why is this complex coloured? Explain on the basis of distribution of electrons in the d –
orbitals?
3
c) How does the colour change on heating TiH 2O6  ion?
3
AHLCON PUBLIC SCHOOL, MAYUR VIHAR – I, DELHI – 110091.
CHEMISTRY - XII (2014 – 2015)
Assignment No: 2
P-Block Element
1.
Explain why CS2 is stable but CSe2 is not?
2.
PCl5 has high m.pt. Why?
3.
H3PO2 is strong reducing agent. Explain why?
4.
Nitrogen does not form pentahalides. Why?
5.
Why does NO2 dimerise?
6.
Why NCl3 get readily hydrolysed but NF3 does not?
7.
Bismuth is strong oxidising agent in pertavalent state. Why ?
8.
Sulphur has greater tendency for catenation than any other group element?
9.
SF6 is inert towards hydrolysis while SF4 hydrolyses easily.
10.
The bond energy of F2 is less than that of Cl2. Why?
11.
ClF3 exists but FCl3 does not?
12.
Metal fluorides are more ionic than metal chlorides. Why?
13.
Though fluorine is most electronegative but HF is weak acid among all halogen acids?
14.
The bond angle in NH3 is greater than bond angle in PH3.
15.
Out of F, Cl, Br and I which has the highest negative electron gain enthalpy?
16.
Molten ICl yields I2 at cathodes on electrolysis. Explain?
17.
What is the basicity of H3PO4?
18.
Element ‘A’ burns in nitrogen to given an ionic compound ‘B’ which reacts with water to
give ‘C’ and ‘D’. The solution ‘C’ becomes milky on bubbling CO2 gas. Identify A, B, C,
and D.
19.
Arrange the following in decreasing order of the property indicated.
i) F2, Cl2 , Br2 , I2 (Bond dissociation Energy)
ii) HF , HCl, HBr, HI (Acid strength in water)
iii) H2O , H2S , H2Se , H2Te (Boiling point)
iv) NH3 , PH3 , ASH3 , SbH3 (Basic Strength)
20.
SO2 can act as both oxidising agent and reducing agent while SO3 can act only as oxidising
agent. Explain?
21.
NO is paramagnetic in the gaseous state but diamagnetic in solid and liquid states justify.
22.
Oxides of phorphorus have cage like structures.
23.
Solubility of Iodine in water may be increased by adding potassium iodide. Explain?
24.
Dipole moment of NH3 is greater than that of NF3. Why?
25.
Why is BiH3 the strongest reducing agent among the hydrides of group 15 elements?
26.
Sulphur is solid while oxygen is a gas at room temperature.
27.
Compounds like P(C2H5)3 and As (C6H5)3 act as ligands. Why?
28.
SnCl4 is a covalent liquid but SnCl2 is ionic solid why?
29.
Noble gases have very low B.pts. Why?
30.
An element ‘A’ exists as a yellow solid in standard state. If forms volatile hydride ‘B’ which
is a foul smelling gas and is extensively used in analysis of salts. When treated with oxygen
‘B’ forum an oxide ‘C’ which is a colourless punjent smelling gas. This gas when passed
through acidified KMnO4 solution decolourises it. ‘C’ gets oxidized to another oxide ‘D’ in
the presence of heterogeneous catalyst. Identify A, B, C, D. Write chemical equation for the
conversion of ‘C’ to ‘D’.
31. Nitrogen fertilizers are commonly used to promote the growth of plants and boost the crop
yields. As a student of chemistry, can you suggest a farmer whether he should use excess N2
fertilizers to get max. yield or not?
32. When conc. H 2 SO4 was added to an unknown salt present in a test tube, a brown gas (A) was
evolved. The gas intensified when Cu turnings were also added into this test tube. On
cooling the gas A changed into a colourless gas (B).
i)
ii)
Identify the gases (A) and (B).
Write the equations for the reactions involved.
33. When a mixture of NH 4Cl and K 2CrO7 are heated, stable colourless gas (A) was evolved
which did not support combustion but magnesium continued to burn in it. The gas (A)
reacted with calcium carbide in an electric furnanance forming a solid (B). The compound
(B) was slowly hydrolysed by water forming an insoluble substance (C) and the solution of
substance (D) which turned Nessler’s reagent brown. Identify (A) to (E) and give the
reactions involved.
34. A translucent white waxy solid (A) on heating in an inert atmosphere is converted to its
allotropic form (B). Allotrope (A) on reaction with very dilute aqueous KOH liberates a
highly poisonous gas (C) having rotten fish smell with excess of chlorine forms (D) which
hydrolyses to compound (E). Identify compounds (A) to (E).
35. Nitrogen fertilizers are commonly used to promote the growth of plants and boost the crop
yields. As a student of chemistry, can you suggest a farmer whether he should use excess N2
fertilizers to get max. yield or not?
36. When conc. H 2 SO4 was added to an unknown salt present in a test tube, a brown gas (A) was
evolved. The gas intensified when Cu turnings were also added into this test tube. On
cooling the gas A changed into a colourless gas (B).
iii)
iv)
Identify the gases (A) and (B).
Write the equations for the reactions involved.
37. When a mixture of NH 4Cl and K 2 Cr2 O7 are heated, stable colourless gas (A) was evolved
which did not support combustion but magnesium continued to burn in it. The gas (A)
reacted with calcium carbide in an electric furnanance forming a solid (B). The compound
(B) was slowly hydrolysed by water forming an insoluble substance (C) and the solution of
substance (D) which turned Nessler’s reagent brown. Identify (A) to (E) and give the
reactions involved.
38. A translucent white waxy solid (A) on heating in an inert atmosphere converted to its
allotropic form (B). Allotrope (A) on reaction with very dilute aqueous KOH liberates a
highly poisonous gas (C) having rotten fish smell with excess of chlorine forms (D) which
hydrolyses to compound (E). Identify compounds (A) to (E).
AHLCON PUBLIC SCHOOL, MAYUR VIHAR – I, DELHI – 110091.
Assignment No: 3
BIO MOLECULES
CHEMISTRY - XII
Q.1
Ans.
Why are carbohydrates generally optically active?
They have at least a chiral carbon atom, hence they are generally optically active.
Q.2
Ans.
Write the equilibrium equation when  or  - glucose is dissolved in water?
 - glucose
open chain form
 - glucose
(36%)
(0.02%)
(67%)
Q.3
Of the following which is sweetest?
Sucrose, glucose, fructose, galactose, maltose and lactose.
Sucrose.
Ans.
Q.4
Ans.
What is the name given to the linkage which holds together two monosaccharide units in a
Polysaccharide?
Glycosidic linkage.
Q.5
Ans.
Out of the two – amylose and amylopectin, which one is water soluble?
Amylose is water soluble whereas amylopectin is water insoluble.
Q.6
Ans.
Out of two – amylose and amylopectin which one is a linear Polymer of  - glucose?
Amylose is a linear polymer whereas amylopectin is branched chain polymer of  - glucose.
Q.7
Ans.
What is the structural difference in the monomers of starch and cellulose?
The monomers of starch is  - glucose and that of cellulose is  - glucose. The only
difference is in the position of H and OH is at carbon one.
Q.8
Ans.
What is the constituent units of cellulose?
Cellulose is a linear polymer of - glucose units.
Q.9
Which disease is caused due to the deficiency of the following?
1. Protein
2. Essential amino acids in diet
3. Vitamin A
4. Vitamin B1 (Thiamine)
5. Vitamin B2 (Riboflavin)
6. Vitamin B6 (Pyridoxine)
7. Vitamin B12
8. Vitamin C
9. Vitamin D
10. Vitamin E
11. Vitamin K
Disease
Kwashiorkar
Kwashiorkar
Xerophthalmia, Night blindness
Beri – beri
Cheilosis
Convulsions
Pernicious anaemia
Scurvy
Rickets
Increased fragility of RBC’s and muscular weakness
Increased blood clotting time
Q.10
Ans.
What type of bonding occurs in  - helix configuration?
Hydrogen bonding.
Q.11
Ans.
What type of bonding occurs in - pleated sheet configuration
H- bonding.
Q.12
Ans.
What type of structure occurs in globular proteins?
They have ball like 3-D configuration. These are formed when the helical coils are looped,
thereby leaving very little space in between.
Q.13
What are reducing and non-reducing sugars? What is the structural feature characterizing
reducing sugars?
Reducing sugars are those which reduce fehling’s solution and Tollen’s reagent, on the other
hand non-reducing sugars are those which don’t reduce Fehling’s solution and Tollen’s
reagent. Reducing sugars contain free – CHO and COgp. Whereas non-reducing doesn’t
contain free – CHO or CO gp.
Ans.
Q.14
Ans.
Amylose and cellulose are both straight chain polysaccharides containing only D-glucose
units. What is the structural difference between the two?
In amylose the two D-glucose units are joined by  - linkage In cellulose, it is joined by
 - link.
Q.15
Ans.
What are essential and non-essential amino acids?
Non-essential – which can be synthesized in the body.
Essential – which can’t be synthesized in the body and must be obtained through diet.
Q.16
Ans.
Write the names of enzymes whose deficiency causes albinism and Phenyl Ketone urea?
Albinism – tyrosinase
Phenyl Ketone urea – Phenyl alanine hydroxylase.
Q.17
a)
Ans.
Give reasons for the following :Amino acids have relatively higher melting point as compared to corresponding halo acids.
Because they behave like salts rather than amines or carboxylic acids. This is due to the p/o
both an acidic and a basic amino gp. in the same molecule.
R-CHCOOH
|
NH2
b)
Ans.
Amino acids are amphoteric in behaviour.
Because they form Zwitter ion and can react both with acids and alkalies.
c)
Ans.
On electrolysis in acidic solution amino acids migrate towards cathode while in alkaline
solution these migrate towards anode?
Because in acidic solution the amino acid has a +ve charge on NH3 and hence migrate
towards cathode whereas in basic soln, there is no +ve charge on NH3, but have a –ve charge
on COO- and hence migrate towards anode.
d)
Ans.
The monoamino monocarboxylic acids have two PK values?
Because they exists in two forms to give two PK values.
Q.18
What type of linkages are responsible for the formation of :i) Primary Structure of Proteins
ii) Cross linking of polypeptide chains
iii)  - Helix formation
iv)  - sheet structure
Ans.
i) Covalent bonding
ii) Disulphide bridges, ionic or salt bridges and H-bonding
iii) Intra molecular H-bonding b/w – NH and – C = 0
iv) Inter molecular H – bonding.
Q.19
What happens when D-glucose is treated with the following reagents:i) HI
ii) Bromine water
iii) HNO3
CHO
Ans.
i) (CHOH ) 4
CH 2OH
HI

CH 3CH 2CH 2CH 2CH 2CH3
(n  hexane)
COOH
CHO
ii) (CHOH ) 4
CH 2OH
Br2 water
or
CH 2OH
(Gluconicacid )
Glu cos e
iii)
(CHOH ) 4
COOH
HNO3
CHOH 4
Gluconic
COOH
acid
( Saccharica cid
Q.20
In what form carbohydrates are stored in animal body and plants?
Ans.
Glycogen in animal body and starch in plants.
Q.21
The two strands in DNA are not identical but are complimentary. Explain?
Ans.
The two strands in DNA molecule are held together by hydrogen bonds between purine base
of one strand and pyrimidine base of the other and vice-versa. Because of different sizes and
geometries of the bases, the only possible pairing in DNA are G (guanine) and C (Cytosine),
through three H – bonds i.e. (C = G) and between A (Adenine) and T (thiamine) through two
H – bonds (i.e. A = T). Due to this base pairing principle, the sequence of bases in one strand
automatically fixes the sequence of bases in the other strand. Thus, the two strands are
complimentary and not identical.
Q.22
Ans.
What are different types of RNA formed in the cell?
i) Ribosomal RNA (r – RNA)
ii) Messenger RNA (m – RNA)
iii) Transfer RNA (t – RNA)
Q.23
What type of bonding helps in stabilizing the  - Helix structure of proteins?
Ans.
The  - Helix structure of proteins is stabilized by intramoleculer H – bonding between
C = 0 of one amino acid residue and the N – H of the fourth amino acid residue in the chain.
Q.24
If one strand of a DNA has the sequence – ATGCTTCA. What is the sequence of the bases in
the complimentary strand?
Ans.
ATGCTTCA
TACGAAGT
Q.25
Explain why vitamin C cannot be stored in the body?
Ans.
Vitamin C is water soluble, therefore, it is readily excreted in urine and hence cannot be
stored in the body.
Q.26
Two samples of DNA, A and B have melting temperature. ™ 340 and 350K respectively.
Can you draw any conclusion from these data regarding their base content?
Ans.
In CG base pair there are 3 H – bonds and in AT has two H – bonds, :. CG base pair is more
stable than AT base pair. Since sample B has higher M.Pt. than sample A, sample B has
higher CG content as compared to sample A.
Q.26
A compound A C6 H12O6  is oxidised by bromine water into monobasic acid. It also reduces
Tollen’s reagent and reacts with HCN to give a compound (C). On heating C with HI/ red P,
n – heptanoic acid is obtained. Compound A on treatment with excess phenyl hydrazine gave
D – glucosazone. Name the compound A and draw its cyclic form.
α - D (+) Glucose
β - D (+) Glucose
AHLCON PUBLIC SCHOOL
ASSIGNMENT : 4
ELECTRO CHEMISTRY
CLASS – XII
1Mark Questions:
Q.1
Q.2
Q.3
Q.4
Q.5
What is meant by standard electrode potential?
Which cell was used in Appollo space programme? What was the product used for?
What is the purpose of a salt bridge placed between two half cells of a galvanic cell?
How is electrode potential different from a cell potential?
Why is the effect of temperature on the electrical conduction of (i) metallic conductor
(ii) electrolytic conductor.
Which electrolyte is used in a drycell?
Write Debye-Huckel onsagar equation. What do different symbols signify?
Write the Nernest equation for the reaction.
Q.6
Q.7
Q.8
2Cr  3Fe    2Cr 3  3Fe
2Mark Questions
Q.9
For concentration cell
cu ( s) cu 2 (0.01m) cu 2 (0.1m) cu ( s)
i)
ii)
Calculate the cell potential
Will the cell generate emf when concentration becomes equal.
[Ans. 0.0295V,No]
Q.10
State and explain kohlrausch laws of independent migration of ions with a suitable example
Q.11
Write two application of Kohlrausch law.
Q.12
The measured resistance of a conductance cell containing 7.5  10-3 M solution of KCl at
25oC is 1005 ohms. Calculate (a) specific conductance
b) molar conductance of the
solution.
Cell constant = 1.25cm-1
[Ans. a) 0.001244 ohm-1 cm-1
b) 165.87 ohm-1 cm2 mol-1]
Q.13
The conductivity of 0.001m acetic acid is 4.95  10 – 5 scm-1. Calculate its dissociation
constant.
(acetic acid) = 390.5 s cm2 mol -1
[Ans. = 1.85  10-5 ]
Q.14
Can a Nickel spoon be used to stir a solution of silver nitrate? Support your answer with
reason.
( EoNi2+/Ni = -0.25V
EoAg+/Ag = 0.80V).
Q.15
A 100W, 220V incandscent lamp is connected in series with an electrolytic cell containing
copper sulphate solution what weight of copper will be deposited by the current flowing for 5
hours?
At mass of Cu = 63.54)
[Ans. 2.69g]
The standard reduction potentials are as given below:
Half cell
Eovalue
Q.16
Zn(OH) 2/Zn
Mg(OH) 2/Mg
Fe(OH) 2/Fe
Al(OH)2 Al
Under standard conditions.
-1.245V
-2.690V
-0.877V
-2.30V
i) Which is the strongest reducing agent?
ii) Which reducing agent could reduce Zn(OH)2 to Zn?
iii) Which reducing agent could reduce Fe(OH)2 to Fe?
Q.17
Account for the following
a) Anodic medium inhibits the rusting of iron.
b) Iron does not rust even if the Zinc coating is broken in a galvanized iron pipe.
Q.18
Q.19
Cu 2 2e  Cu E o  0.34V
Ag e  Ag E o  0.80V
a) Construct a galvanic cell using the above data
b) For what concentration of Ag+ ions will the emf of the cell be zero at 25oc.,if the
concentration of Cu2+ is 0.01 M
(log 3.919 = 0.593)
[Ans = 1.59  10-9 M]
Calculate the maximum possible electrical work that can be obtained from the following cell
under the standard conditions at 25oC
Zn Zn 2 (aq) Co 2 (aq) Co
EZn 2 / Zn  0.76V
ECo2+/Co = -0.28V
F = 96500 CMol-1
[Ans. 92.6KJ]
Q.20
How would you explain the sharp in crease in the molar conductivity of a weak electrolyte on
dilution? How is the molar conductivity related to the degree of dissociation of a sparingly
soluble salt?
Q.21
Manpreet went with his father to buy hinges for the door. They showed then two qualities,
the normal iron hinges and the galvanized one. The normal iron hinges wire cheaper while
the galvanized hinges were costlier. Manpreet’s father opted for the cheaper normal iron
hinges. Manpreet intervened and suggested his father to go for galvanized hinges.
a) What was the rationale for Manpreet to buy galvanized hinges?
b) What values are attached to this decision?
Q.22
Suddenly the power went off. There was announcement that the supply will be restored after
12 hours. It was 8 p.m. and Ranjeet had to appear for the Chemistry paper the next morning.
What to do? Candles were not available either. “Mom, are there lemons in the house?” cried
Ranjeet. “Yes, son, we have four lemons in the fridge.” Answered the mother. That is fine.
Ranjeet made some assembly, light was seen in the house and he could prepare for the
examination.
a) Can you given how Ranjeet could manage to obtain light?
b) What values are attached to Ranjeet’s initiative?
Q.23
It was summer vacation in the school. Mohan, Natwar, Rakesh and Jeetu planned to have a
trip to Himachal valley, a 12 feet wide water stream was flowing. A bridge made of iron had
been fixed a few years back to let people cross the stream and go to the other side. The
friends observed that the bridge had been badly rusted and perhaps would not last much of the
time. Moreover, if the bridge collapses suddenly, there would be a loss of life. Having
enjoyed the party there, they discussed how they can contribute to enhance the life of the
bridge.
a) What possibly was the step they took to stop further loss to the bridge?
b) What significance do you attach to their concern for a common cause?
Q.24
Manu and his father went to shop to purchase a battery for their inverter. Shopkeeper showed
them two types of batteries, one with lead plates and the other with cadmium plates. The
battery with cadmium plates was more expensive than the lead battery. Manu’s father wanted
to purchase lead battery as it was cheaper.
a) As a student of chemistry, why would you suggest to Manu’s father to buy the expensive
cadmium plate battery. Give two reasons.
b) What are the values associated with the above decision?
Q.25
Corrosion of copper, silver and rusting of iron are very common. Both cause enormous
damage. Rusting of iron in particular results in the loss of crores of rupees every year. Major
accidents occur because of this.
a)
b)
c)
d)
What is the chemical formula of rust?
Why do silver articles become black when exposed to air for a long time?
How is copper affected by corrosion?
Suggest three ways to check rusting of iron so as to check national wastage of money.
AHLCON PUBLIC SCHOOL
ASSIGNMENT : 4
CHEMICAL KINETICS
CLASS – XII
1. Write the units of 1st order rate constant of gaseous reaction if the partial pressure of gaseous
reaction is given in atm.
2. Identify the reaction order for each of the following rate constant units :
(1) R = 2.5  10 -4 mol -1 LS -1
(2) R = 4.0  10 -4 S -1
3. For the elementary step of a reaction.
A + H2O  B
rate  [A] what is its (a) Molecularity
(b) order of the reaction
4.
Thermal decomposition of HI on gold surface is a zero order reaction.
2HI (g)  H2(g) +
I2(g)
i)
Express the relationship between the rate of production of I2 and rate of disappearance of
HI.
Sketch a graph between Potential Energy and reaction co – ordinate for the reaction.
H2 (g) + I2 (g)  2HI(g) on the graph sheet. Indicate
5.
(i)
(ii)
(iii)
Activated complex
Activation Energy
Enthalpy of reaction
6.
A substance with initial concentration ‘a’ follows zero order kinetics. In how much time will
the reaction go to completion?
7.
A 1st order reaction is 15% completed in 20 minutes. How long will it take to
complete 60%
8.
Draw a graph between fraction of molecules and kinetic energy of the reacting species for two
different temperatures:
i)
ii)
iii)
Q.9
Room temperature
Temperature 10oC higher than the room temperature
Indicate the fraction of additional molecules which react at (t + 10)oC
For the reaction 2NO( g )  Cl2 ( g )  2NOCl ( g ) the following data were collected. All the
measurements were taken at 263 K.
Exp No.
1
2
3
4
Initial [NO]
(M)
0.15
0.15
0.30
0.25
Initial (Cl2)
(M)
0.15
0.30
0.15
0.25
Initial route of disappearance of
Cl2 (M/Min)
0.60
1.20
2.40
?
a) Write the expression for rate law.
b) Calculate the value of rate constant and specify its units.
c) What is the initial rate of disappearance of Cl2 in exp. 4.
Q.10
A given sample of milk turns sour at room temperature (20oC) in 64 hours. In a refrigerator at
3oC, milk can be stored three times as long before it sours. Estimate the activation energy for
souring of milk.
( Hint:
Q.11
CBSE – 2011
K 293
 3, R  2.0Cal )
K 276
(Ans. Ea = 10.454 K Cal)
Rate constant ‘K’ of a reaction varies with temperature ‘T’ according to the equation:
Ea  1 
log K = log A  
2.303R  T 
1
When a graph is plotted for log K vs   , a straight line with a slope of – 4250K is obtained.
T 
Calculate ' Ea ' for the reaction. (R = 8.314 J K-1mol-1)
MULTIPLE CHOICE QUESTIONS:1. The rate law for a reaction between the substances A and B is given by rate K  A B  On
doubling the concentration of A and halving the concentration of B, the ratio of the new rate
to the earlier rate of the reaction will be
x
1 ( m  n)
2
b. ( m  n)
m
c. ( n  m)
a.
d. 2 ( nm)
2. If concentration of reactants is increased by ‘x’, the rate constant K becomes:
a. e
k
x
c. k
x
b. k x
d.
k
(Hint: Rate const is characteristic constant for a given reaction)
3. A reaction proceeds in three stages. The first stage is slow and involves two molecules of
reactants. The second and third stage are fast. The overall order of the reaction is
a. first order
b. second order
c. third order
d. zero order
4. The rate constant of a reaction depends on
a. temperature
b. initial concentration of the reactants
c. time of reaction
d. extent of reaction
5. The activation energy for a chemical reaction does not depend upon
a. temperature
b. nature of reacting species
c. frequency factor
d. concentration of reacting species.
6. The activation energy of a reaction is zero. The rate constant of reaction
a.
b.
c.
d.
increases with increase of temperature
decreases with decrease of temperature
decreases with increase of temperature
independent of temperature.
[Hint K = AC-Ea/RT)
7. When ethyl acetate was hydrolysed in presence of 0.1 N HCl, the rate constant was found to
be 5.40 10 5 sec 1 . But when 0.1N H 2 SO4 was used for hydrolysis, the rate constant was
found to be 6.25 10 5 sec 1 . Thus it may be concluded that;
a)
b)
c)
d)
H 2 SO4 is stronger than HCl
H 2 SO4 is weaker than HCl;
H 2 SO4 and HCl both have same strength.
The data are not sufficient to compare the strength of H 2 SO4 and HCl.
8. The reaction L  M is started with 10g of L. After 30 and 90 minute, 5.0g and 1.25 g of L
are left respectively. The order of reaction is
a) zero
b) seecond
[Ans: 1. d
c. first
d. third
2. c 3. b
4. a
5. d
6. d
7. a
8. c]
AHLCON PUBLIC SCHOOL
CLASS XII
ORGANIC CHEMISTRY
Q.1
Draw the structural isomer of C3 H 6Cl2 which can exhibit enantiomerism.
Q.2
What is meant by centre of symmetry?
Q.3
What is meant by specific rotation?
Q.4
What are meso compounds?
Q.5
Mention a chemical property in which methanoic acid differs from acetic acid.
i)
Red ppt with Fehling reagent.
ii)
Silver mirror test
iii)
2HgCl 2  HCOOH  Hg 2 Cl2  2HCl  CO2
whiteppt
Q.6
Why B.pt of CH 3 NH 2 is less than that of methanoic acid.
Q.7
Chloroform is stored under dark coloured bottles, completely filled why?
Q.8
Cyclobutyl bromide on treatment with magnesium in dry ether forms an organo metallic
compound A. Compound A reacts with acetaldehyde to form an alcohol B. After mild
acidification B is treated with HBr to give C. Write structures of A, B, C where as C is 1 –
Bromo – 1 – cyclo butyl ethane.
Q.9
Three isomers A, B, C of molecular formula C8 H 9 Br gave following compounds upon
oxidation.
i) Benzoic acid
ii) phthalic acid
iii) p – bromobenzoic acid.
A is optically active, both A and B gave yellow ppt when warmed with alc. AgNO3 solution.
Identify A, B, C.
Q.10
An ether [A] C6 H14O when heated with excess of hot concentrated solution of HI produced
two alkyl halides, which upon hycholysis form compound B and C. Oxidation of ‘B’ gave an
acid D where as oxidation of ‘C’ gave a ketone E. Deduce the structure of A, B, C, D, E.
Q.11
An organic compound [A] having molecula formula C6 H 6O gives a characteristic colour with
aqueous FeCl3 solution. When A treated with CO2 and NaOH at 400 k under pressure [B] is
obtained. [B] upon acidification gives [C] which reacts with acetyl chloride to form [D]
which is a popular pain killer. Deduce structures of A, B, C, D.
Q.12
Draw the structure of carbonyl group and predict
i)
ii)
iii)
The state of hybridization of carbon atom in carbonyl group and bond angle in it.
No of  and  bonds.
Identify the nucleophillic and electro phillic centre in it.
Q.13
An organic compound [A] with molecular formula C5 H 8O2 is reduced to n – pentane upon
treatment with Zn – Hg/ HCl. ‘A’ forms dioxine and hydroxyl amine which gives positive
iodoform test and Tollen’s test. Identify compound and deduce its structure.
Q.14
A compound [A] of molecular formula C3 H 7 NO2 which on reaction with Fe & HCl gives
saturated aldehydes containing three carbon atoms. Deduce structures of A, B, C and write
reaction involved.
Q.15
How will you distinguish between
i)
ii)
Chlorobenzene and benzyl chloride?
Benzaldehyde and acetophenone.
Q.16
Convert i) methanol to ethanol
ii) Ethanol to Methanol
Q.17
Kapil and Kavita were revising the chapter on aldehydes and ketones. Having studied the
methods of preparation and properties, they came to uses of these compounds. Kapil told
Kavita that these compounds find use in a number of eatables and perfumeries. The ice cream
that you eat every other day in summer contains an aldehydes. The yagna that you perform
on religious events uses another aldehydes. Many of these compounds are obtained from
plants. These compounds possess pleasant fragrances.
a) Can you tell which of the aldehydes and ketones are obtained from plants?
b) How do you benefit from the knowledge of this class compounds?
Q.18
A compound [A] of molecular formula C3 H 7 NO2 on reaction with Fe and HCl gives
compound B ( C3 H 9 N ) which upon reaction with CrO3 gives saturated aldehyde containing
three C – atoms. Deduce structures of A, B, C and write reactions involved.
AHLCON PUBLIC SCHOOL
ASSIGNMENT : 5
SURFACE CHEMISTRY
CLASS – XII
Very Short answer type questions (1 mark each)
1.
2.
3.
4.
5.
6.
Define Electrophoresis.
What is meant by shape selective catalyst?
What is meant by chemisorption?
Why is a finely divided substance more effective as an adsorbent?
What is an emulsion?
Which of the following is most effective electrolyte in the coagulation of
Fe2O3 .H 2O / Fe3 sol ?
KCl , AlCl3 , MgCl2 , K 4 FeCN 6 
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Name the type of potential difference produced between the fixed charged layer and
diffused layer having opposite charges around the colloidal particle. (Electro kinetic
potential or zeta potential)
Why is ferric chloride preferred over potassium chloride in case of a cut leading to
bleeding?
Why is gelatin added to ice creams? (emulsifying agent)
Why are some medicines more effective in colloidal form? (more surface area & easily
assimilated)
Why it is important to have clean surface in surface studies?
What is Collodion?
Why the white precipitate of silver halide does becomes coloured in the presence of the
dye eosin?
Of NH3 and N2 which gas would be adsorbed more readily on the surface of charcoal and
why?
Why is desorption important for a substances to act as good catalyst?
Why does sky appears blue in colour?
Question No. 11 to 16 are written at the back. Please add them in this category.
Answer the following questions:1. What is adsorption?
2. Name some common adsorbents.
3. What role does adsorption play in heterogeneous catalysis?
4. How does adsorption of a gas on a solid surface vary with
a. Temperature (b) pressure? Illustrate with the help of appropriate graphs.
5. How can the constants K and n of the Freundlich adsorption equation be calculated?
6. How does adsorption help in
a. Chromatographic analysis. b) curing diseases
c) making indicators
d) concentration of ores.
7. Describe some features of catalysis by zeolites.
8. Name two industrial process in which hetrogenous catalysis are employed.
9. Give the sources and reactions catalysed by the following enzymes.
a) Pepsin
b) maltase
c) Urease
d) invertase
10. How does the rate of enzyme – catalyzed reactions vary with a) temperature
b) PH.
11. How are multimolecular colloids different from macro – molecular colloids?
12. State the relationship between the quantity of gas adsorbed by a solid adsorbent and the
pressure of the gas.
13. Write the name of the catalyst used in the following process:i) Hydrolysis of the methyl acetate.
ii) Oxidation of ammonia into nitric acid by ostwald process.
14. Name a zeolite catalyst which directly convert alchohol into gasoline.
15. Distinguish between a promoter and poision of a catalyst.
16. What is the importance of critical temperature in respect of adsorption of gases?
17. Classify the following processes into absorption, adsorption or sorption.
i)
Anhy. CaCl2 placed in the atmosphere saturated with H2O.
ii)
Silica gel placed in the atmosphere saturated with H2O.
iii)
A chalkstick dipped in ink.
iv)
Addition of animal charcoal to methylene blue.
18. How is the phenomenon of adsorption helpful in
i)
Production of high Vacuum
ii)
Control of humidity
iii)
Separation of inert gases
iv)
Froth flotation process
19. Account for the following:i)
ii)
A delta is formed at the point where the river enters the sea.
Artificial rain can be caused by spraying electrified sand on the clouds.
20. How are enzymes different from catalysts?
21. Name a silver sol used as an eye – lotion.
VALUE BASED QUESTION
22. Ashok was lying on his bed & suddenly he observed something. A ray of light was entering
through a small hole in the ventilator. He observed that the ray of light converted into bright
cone and tiny particles were seen in the cone of light. He called his friend Amrit who was a
student of chemistry, to his home and asked him how this was happening.
a) Can you predict what explanation was given by Amrit?
b) Analyse the attitude of both Ashok and Amrit?
a) Tyndall effect
b) Good observation of knowledge of
chemical principles
AHLCON PUBLIC SCHOOL
CLASS XII – ASSIGNMENT
CHEMISTRY – TOPIC: THE SOLID STATE
1MARK QUESTIONS
Q.1
What is meant by long range order in crystals?
Q.2
Name the crystal defect produced when NaCl crystal is doped with MgCl2.
Q.3
What is the coordination number of Cs in cesium chloride.
Q.4
Which point defect in the crystals increases, the density of the solid?
Q.5
What type of stoichiometric defect is shown by
i) ZnS and (ii) AgBr?
Q.6
How will you convert CsCl structure into NaCl structure?
Q.7
What type of crystal defect is indicated in the diagram below.

Na +
Cl -
Cl -
Na +
Cl -
Na +
a) Frenkel and Schotty defects
Cl -
Na +
Cl -
b) Schotty defect
Na +
c) Interstitial defect
Na +
Cl -
Na +
Cl -
Na +
Cl -
Na +
Cl –
d) Frenkel defect
2Mark Questions:Q.8
Account for the following a) solids are rigid
b) solids have a definite volume.
Q.9
What makes alkali metal halides sometimes coloured?
Q.10
An ionic compound AB2 possess CaF2 type crystal structure. What are the coordination
numbers of A2+ and B- ions in crystal of AB2.
Q.11
At what temperature range, do most of the metals become super – conductor?
3Mark questions:Q.12
Write and explain the differences between consequences of Schottky and Frenkel defects
under the following headings.
a) Effect on density
b) Effect on electrical conductivity
c) Effect on stability of the crystal.
Q.13
A goldsmith under training was asked by his boss to make bangles of gold. He used a bar of
24 carat for this purpose. The bangles made by him were so soft that they could be easily
bent. The boss told him not to use pure gold but rather 22 carat gold. The bangles were now
quite hard and could not be bent on applying some force.
a)
b)
c)
d)
What was the mistake committed by goldsmith?
Why did boss ask him to use 22 carat gold?
In what way is 22 carat gold better than 24 carat gold?
What is the value associated with this?
Q.14
A student working in the laboratory passed electric current through a rod of copper as well as
solid copper sulphate crystals. To his surprise, the current could pass through copper rod
connected in a cell and not through the crystals.
a) Was his observation correct?
b) What was the reason behind this observation?
c) How is this behaviour helpful in explaining conducting of electrolytes?
Q.15
In India, there is shortage of electricity, people have to face big cuts particularly when the
summer is in peak. Industry has to suffer a lot. Conventional sources of electricity such as
hydel power, thermal power and even nuclear power etc. fail to meet the ever growing
demand of electricity. Now a days, there is emphasis on the use of solar energy. Photovoltaic
material can convert solar energy into electrical energy.
a)
b)
c)
d)
What are the drawbacks of traditional source of electricity?
How is solar energy better than conventional source of energy?
Why is solar power not very popular in India?
What is the value associated with the use of solar energy?
NUMERICALS
Q.16
If the close packed cations in an AB type solid have a radius of 75 pm, what would be the
maximum and minimum sizes of the anions filling the voids?
[ Ans. 102.5 pm, 181.2 pm]
Q.17
Cscl has bcc arrangement and its unit cell edge length is 400 pm. Calculate the interionic
distance in cscl.
[Ans. 346.4pm.]
Q.18 The radius of an atom of an element is 500 pm. If it crystallizes as a face centred cubic lattice,
what is the length of the side of the unit cell.
[Ans. 1414 pm.]
Q.19 The unit cube length for LiCl (Nacl structure) is 5.14Ao. Assuming anion – anion contact,
calculate the ionic radius for chloride ion.
[Ans. 1.81 Ao.]
Q.20 An element A crystallizes in f.c.c structure. 200 g of this element has 4.12  1024 atoms. The
density of A is 7.2 g cm -3. Calculate the edge length of the unit cell.
[Ans. 299.9 pm.]
Q.21 Calculate the density of silver which crystallizes in a f. c. c structure. The distance between the
nearest silver atoms in this structure is 287 pm. (Molar mass of Ag = 107.87 g mol -1,
Na = 6.02  10 23 mol -1).
Q.22 Write a point of distinction between a metallic solid and an ionic solid other than metallic
luster.
Q.23 Tungsten crystallizes in a b.c.c unit cell. If the edge of the unit cell, is 316.5 pm. What is the
radius of tungsten atom?
Q.24 Iron has a b.c.c unit cell with a cell dimension of 286.65pm. The density of iron is 78.74cm-3.
Using this information calculate Avogadro’s number. (at. Mass Fe – 55.8u)
AHLCON PUBLIC SCHOOL
CHEMISTRY ASSIGNMENT :
SOLUTIONS
CLASS – XII
Multiple Choice Questions (One answer correct)
Q.1
Assuming each salt to be 90% disassociated, which of the followings will have highest
osmotic pressure.
a) Decimolar Al2(SO4)3
b) Decimolar BaCl2
c) Decimolar Na2SO4
d) A solution obtained by mixing equal volumes of (b) and (c) and filtering.
Q.2
The boiling point of an azeotropic mixture of water and ethyl alcohol is less than that of
theoretical value of water and alcohol mixture. Hence, the mixture shows:
a)
b)
c)
d)
That solution is highly saturated
Positive deviation prove Raoult’s Law.
Negative deviation from Raoult’s Law.
Nothing can be said.
Q.3
On mixing 10 ml of acetone with 40 ml of chloroform, the total volume of the solution is :
a) less than 50 ml
b) more than 50 ml
c) equal to 50 ml
d) cannot be predicted.
Q.4
The factor T f / K f represents:
a)
b)
c)
d)
molarity
formality
normality
molality
Q.5
A teacher one day pointed out to her students the peculiar fact that water is a unique liquid
which freezes exactly at 0oC and boils exactly at 100oC.
a) water dissolves anything however sparingly the dissolution may be
b) water is a polar molecule
c) boiling and freezing temperatures of water were used to define a temperature scale
d) liquid water is denser than ice.
Q.6
When an ideal binary solution is in equilibrium with its vapour, molar ratio of the two
components in the solution and in the vapour phase is
a) same
b) different
c) may or may not be same depending upon volatile nature of the two components.
d) None of the above.
[Hint: Recall that PA|  PM  X A (in vapour phase)  P o  X A (in liquid phase)
Q.7
An aqueous solution containing liquid A (M.M – 128.0u) 64% by weight has a vapour
pressure of 145 mm. Find the vapour pressure of A, if that of water is 155 mm at the same
temperature. (Hint: PM  PA|  PB| )
(Ans: PAo|  105 mm)
Q.8
What weight of non volatile solute (urea) NH2CONH2 needs to be dissolved in 100g of water
in order to decrease the vapour pressure of water by 25%? What will be the molality of
solution?
P o  Ps W  18
W 100

, molality of the solution 
(first find W, using it find out
m W
Ps
m W
molality)
(Ans: W = 111.11g m = 18.52g Kg-1)
(Hint:
Q.9
An equeous solution of glucose boils at 100.01oC. The molal elevation constant for water is
0.5K Kg mol-1. What is the number of glucose molecules in the solution containing 100g
water?
(Hint: using Tb  K b .m , calculate W and than number of glucose molecules.)
( Ans: 1.2  1021 molecules)
Q.10
When solid CaCl2 is added to liquid water, the temperature rises. When solid CaCl2 is added
to ice at 0oC, the temperature falls. Explain.
Q.11
A motor vehicle radiator was filled with 8.0 litre of water to which 2.0 litre of methyl alcohol
density 0.8g/ml) were added what is the lowest temperature at which the vehicle can be
parked outdoors without a danger that the water in radiator will freeze? (Kf for H2O =
1.86mol-1Kg) ( Hint: W = 2000  0.8g)
(Ans: T fS  11.6250 C )
Q.12
At 300K, two solutions of glucose in water of concentration 0.01 M and 0.001M are separated
by semi permeable membrane with respect to water on which solution pressure needs to be
applied to prevent osmosis. Calculate magnitude of applied pressure.
(Hint: Calculate 1 and  2 and calculate 1 -  2 )
(0.2217atm)
Q.13
Calculate osmotic pressure of a solution obtained by mixing 100ml of 3.4% (wt/vol) solution
of urea (m.wt – 60u) and 100 ml of 1.6% solution of cane sugar (M.Wt 342.0u) at 20oC.
(Hint:  solution   sugar   ureaV  0.2 Lt )
(Ans:-   7.38atm )
Q.14
Phenol associates in benzene to form dimer. A solution containing 20 x 10 -3 Kg of phenol in
1Kg of benzene has freezing point depression of 0.69 K. Calculate percentage association of
phenol.
1000  Kg  w 

 1     )
(Hint: For association T 
(73.4%)
m W
n

Q.15
Define the following terms
a) Mole fraction
Q.16
Q.17
b) isotonic solutions
c) Van’t Hoff factor
d) Ideal solution.
(CBSE– 2011)
180 g of glucose, C6 H12O6 is dissolved in 1.0 Kg of water in a container. At what
temperature will this solution boil?
(M. Mass of glucose – 180 gmol-1, Kb for water = 0.52 K Kg mol-1, boiling point of pure
water – 373.15K)
(CBSE – 2012)
Determine the osmotic pressure of a solution prepared by dissolving 2.5  10 2 g of K 2 SO4 in
2.0L of water at 25oC, assuming that it is completely dissociated.
(R = 0.0821L at mK-1 mol-1, Molar mass of K 2 SO4 = 174.0g mol-1)
(CBSE – 2012)
Q.18
Satish and Abdul were enjoying weekend at Abdul’s house. Abdul said, “Look Satish, I will
show you something that will surprise you greatly”. “What is that”? asked Satish curiously.
Abdul brought something from his study room. Satish was amazed. He saw a big egg placed
in water in a bottle whose neck was much smaller than the egg in the bottle. “Friend how
could you do that?”, asked Satish.
a) Can you explain the theory behind it?
b) What credit would you give to Abdul for performing this experiment?
Q.19
Henry’s law constant for the molality of methane in benzene at 298 K is 4.27  105 mm Hg .
Calculate the solubility of methane in benzene at 298 K under 760 mm Hg.
(Ans: x = 1.78  10 3 )
Click on the icon to view file:Adobe Acrobat
Document