Download 2002

CHE-05
Assignment Booklet
Bachelor’s Degree Programme (B.Sc.)
Organic Chemistry
CHE-05
School of Sciences
Indira Gandhi National Open University
New Delhi
2002
Dear Students,
As explained in the programme guide for B.Sc. Programme, you have to do 2 Assignments for this elective
courses in Organic Chemistry. Both of these Assignments are Tutor Marked (TMAs).
The blockwise distribution of assignments is as follows:
–
–
Assignment-01 (TMA)
Assignment-02 (TMA)
(Blocks 1 and 2)
(Blocks 3 and 4)
Instructions for Formating Your Assignments
Before attempting the assignments, please read the following instructions carefully.
1. On top of the first page of each TMA answer sheet, please write the details exactly in the following
format:
Enrolment No : .........................……………
Name : ........................…………….
Address : ........................…………….
Course Code
: ........................……………
…...………………………..
Course Title
: .......................…………….
…………………………….
Assignment No : ......................…………….
Study Centre
Date : ………...........................…..
: ...........................................
PLEASE FOLLOW THE ABOVE FORMAT STRICTLY TO FACILITATE EVALUATION AND
TO AVOID DELAY.
2. Use only foolscap size writing paper of good quality (but not of very thin variety) for writing your
answers.
3. Leave 4 cm margin on the left, top and bottom of your answer sheet.
4. Your answers should be precise.
5. While solving problems, clearly indicate the question number along with the part being solved.
6. The validity of the assignments has now been extended to one year. This means that these
assignments can be submitted upto June 2003. If you submit these assignments by 31 st October
2002 you will be permitted to appear in December, 2002 exam. And, if you submit these
assignments by 30th April, 2003 you can appear in June 2003 exam. However, we will advise you to
pace your studies and submit the assignments by the following dates:
Assignment Nos.
Date of submission
Where to send
Assignment-01 (TMA)
30-06-2002
The Co-ordinator of your study centre
Assignment-02 (TMA)
31-10-2002
The Co-ordinator of your study centre
7. Answer sheets received after the due date shall not be accepted.
8. We strongly suggest that you should retain a copy of your assignment.
Wishing you all good luck.
2
Assignment – 01
(Tutor Marked Assignment)
Organic Chemistry
Elective Course in Chemistry
Course Code: CHE – 05
Assignment Code: CHE –05/TMA – 01/2002
Maximum Marks: 100
Answer all questions.
1.
(a) Give the IUPAC names of the following compounds:
(i)
(6)
CH3
|
CH3C = CHCH3
CH3
O
|
||
(ii) CH3CHCH2CH2CH2CCH3
(iii) CH3CH2CN
(b) Write structures of the following compounds:
(4)
(i) 3-ethyl-3-hexanol
(ii) 1-bromo-1-phenylpropane
2.
(a) Name the type of isomerism exhibited by the following pairs of compounds: (5)
(i)
(ii)
(iii)
(iv)
(v)
butanone and butanal
2-methylpropane and butane
1-bromobutane and 2-bromobutane
cis-2-phenylbutene and trans-2-phenylbutene
(R)-2-butanol and (S)-2-butanol
(b) Label the chiral carbon atom in the following compounds by the
asterisk (*) mark :
(i)
OH Br
| |
CH3CH2C – CCH3
| |
Cl H
(ii)
CH3CH2CHCH3
|
Cl
(iii)
CH3CHClCHClCH3
3
(5)
3.
(a) Are the following pairs of compounds identical or represent enantiomers?
CH3
(i)
H
OH
OH and CH3
Cl
Cl
H
CH2OH
(ii)
(5)
CH3
Cl
H and H
Cl
CH3
CH2OH
(b) Draw the structures of the following:
(5)
(i) (R) – lactic acid
(ii) (S)-2-butanol
4.
Explain the following terms:
Dipole – dipole interactions
Intermolecular hydrogen bonding
Fingerprint region
Chemical shift
Racemic mixture
(i)
(ii)
(iii)
(iv)
(v)
5.
(10)
(a) Why is a tertiary carbocation more stable than the primary carbocation?
Explain.
(5)
(b) Arrange the following in the order mentioned against them:
(5)
(i)
4-nitrophenol, phenol, 2,4,6-trinitrophenol
(in the decreasing order of their acidity)
(ii) N,N-dimethylaniline, aniline N-methylaniline
(in the increasing order of their base strength)
6.
(a) Fill in the blanks:
(3)
(i)
The NMR signal of terminal CH3 protons in propane appears
around ………………
(ii) …………. is used to boost the octane number of petrol.
(iii) Physical constants of alkanes …………with the increase in the number
of carbon atoms.
(b) Write down the approximate composition of the following:
(i) natural gas
4
(2)
(ii) light petrol
(iii) gasoline
(iv) grease
(c) How would you prepare alkanes from the following?
(3)
(i) alkyl halides
(ii) carboxylic acids
(iii) alkenes
(d) Complete the following reactions:
(i)
(2)
hv
CH4 + Cl2 
…………
Cr O / Al O
2 3
2 3
(ii) CH3CH2CH2CH2CH2CH3 

775 K
7.
…………………..
(a) Explain the following terms:
(2)
(i) Betaine
(ii) Regio-specific
(b) Answer the following questions:
(3)
(i) What is the role of –OH in dehydrohalogenation of alkyl halides?
(ii) Why are addition reactions of alkenes exothermic?
(iii) Why is hydroboration reaction described as anti-Markownikoff
addition?
(c) Give the products of the following reactions:
(i)
(3)
O3

 ………… + …………
CH 2 = CH 2
 ………….
(ii) CH2=CH–CH=CH2 
1. (BH3 )2
(iii) CH3(CH2)4CH=CH2 
 ……………
2. H O ,  OH
2
2
(d) Draw molecular orbital diagram of the following:
(i) allene
(ii) ethene
5
(2)
8.
(a) Why is acetylene more acidic than ethene?
(2)
(b) How would you prepare the following compounds from propyne?
(4)
(i)
(ii)
(iii)
(iv)
1, 2-dibromopropane
acetone
acetic acid
propane
(c) Classify the following statements as true or false:
(4)
(i) Propyne is a liquid while 1-butyne is a gas.
(ii) 3-octyne has no NMR absorption for alkynyl hydrogen.
(iii) The IR spectrum of 3-hexyne gives one absorption band in
the region 3300-3100 cm1.
(iv) 3-hexyne dissolves in ether while 3-octyne does not.
9.
(a) What is resonance energy? Explain taking the example of benzene.
(2)
(b) Explain the following:
(4)
(i)
Electron releasing groups when attached to an aromatic ring activate
the ring while electron withdrawing groups deactivate the ring.
(ii) Halogens though they are o- and p-directing, yet they deactivate the
aromatic ring.
(c) Predict the major product of the following reactions and give the mechanism: (4)
10. (a) Draw the orbital picture of pyridine and furan.
6
(3)
(b) Pyridine in less basic than alkyl amines but more basic than pyrrole.
Explain.
(2)
(c) Give the IUPAC names of the following:
(3)
(i)
(ii)
(iii)
(d) Complete the following reactions:
 …………….
(iii) CH2=CHCH=CH2 + C2H5C ≡N 
7
Assignment – 02
(Tutor Marked Assignment)
Organic Chemistry
Elective Course in Chemistry
Course Code : CHE –05
Assignment Code: CHE – 05/TMA-02/2002
Maximum Marks: 100
Answer all questions.
1.
2.
(a) How do you account for the fact that aryl and alkenyl halides are less
reactive towards nucleophilic substitution reactions?
(2)
(b) Explain why is benzyl chloride very reactive under both SN1 and SN2
conditions.
(2)
(c) Write the equation for the formation of alkenes from the reaction of
dehydrobromination of 2- bromobutane. If you expect more than one
product, indicate which alkene is the major product?
(2)
(d) Complete following reactions:
(4)
(i)
NaNO2 -HCl
C6H5NH2 1.
 ………………
2. CuCl/HCl
(ii)
(iii)
(iv)
peroxide

 ………….
CH3CH=CH2 + HBr 
H 2SO 4
C6H5Cl + CCl3CHO  ………………
 ……………..
CHCl3 + C6H5NH2 +3 KOH 
(a) What is Grignard reagent? How is this reagent used in the preparation
of following compounds:
(i)
(ii)
(iii)
(iv)
3.
(5)
alkanes
primary alcohols
tertiary alcohols
carboxylic acids
(b) Phenols are acidic in character while alcohols are almost neutral.
Explain in detail.
(5)
(a) Describe the reaction by which the following may be obtained from
1,2-ethanediol:
(2)
(i)
(ii)
oxalic acid
terylene
8
(b) Outline the simple chemical test that would distinguish between primary,
secondary and tertiary alcohols.
(c) How will you convert phenol into:
(3)
(3)
(i) salicylic acid
(ii) phenolphthalein
(iii) bakelite
4.
(d) How is picric acid prepared?
(2)
(a) How is diethyl ether prepared? How and under what conditions does it
react with:
(4)
(i) hydroiodic acid, and
(ii) sulphuric acid?
(b) Why do thiols differ from alcohols in behaviour?
(2)
(c) Write the necessary condition and reactions to prepare ethanal from
the following:
(2)
(i) ethanol (ii) ethyne
(d) Briefly outline the difference in the behaviour of aliphatic and aromatic
aldehydes taking examples of ethanal and benzaldehyde.
5. (a) Explain the action of following on benzaldehyde:
(i)
(ii)
(iii)
(iv)
6.
(2)
(4)
sodium bisulfite
phenylhydrazine
Tollen’s reagent
potassium cyanide
(b) How would you use a crossed aldol reaction to synthesize
cinnamaldehyde? Write a detailed mechanism for the reaction.
(4)
(c) Write a short note on haloform reaction.
(2)
How would you carry out the following conversions?
(10)
(i)
(ii)
(iii)
(iv)
(v)
toluene to benzoic acid
butanoic acid to 2-hydroxybutanoic acid
benzene to phenol
nitrobenzene to azobenzene
butanedioic acid to butanimide
9
7.
How would you prepare the following?
(10)
(i)
The amino acid leucine having the structure, (CH3)2CHCH2CHCOOH,
using potassium phthalimide
|
NH2
(ii) Cango red dye using coupling reaction
8.
Give the products of the following reactions:
(10)
1. LiAlH 4 , ether
 …………….
CH3COOH 
2. H + , H O
(i)
2
OH,H 2O,
CH3CH2CONHCH3 2.1.
 …………+ …………
H + ,H O
-
(ii)
2
(iii)
O
||
heat
CH3CCH2COOH 
………..
(iv)
(v)
673K
 ……….
CH4 + HNO3 
 …………
CH3CHO + CH3CH2NH2 
9. Explain briefly the following reactions:
(i)
(ii)
(iii)
(iv)
(v)
(10)
Cope elimination
Dieckmann condensation
Henry reaction
Bouveault – Blanc reduction
Kolbe electrolysis
10. (a) Draw the structures of the following compounds:
(5)
(i) adenine
(ii) D-(-)-ribose
(iii)isoprene
(iv) nicotine
(v) adernaline
(b) How would you identify the following?
(i) carboxyl group using 1H-NMR spectrum
(ii) primary and secondary amines using IR spectrum
10
(5)
11