ASSIGNMENT BOOKLET

Bachelor’s Degree Programme (B.Sc.)

ORGANIC CHEMISTRY

(Last Date of Submission: March 31, 2011)

School of Sciences

Indira Gandhi National Open University

Maidan Garhi, New Delhi-110068

(For July, 2010 cycle)

Dear Student,

We hope, you are familiar with the system of evaluation to be followed for the Bachelor’s Degree Programme. At this stage you may probably like to re-read the section on assignments in the Programme Guide that we sent you after your enrolment. A weightage of 30 percent, as you are aware, has been earmarked for continuous evaluation, which would consist of one tutor-marked assignment. The assignment is based on Blocks 1, 2, 3 and 4.

Instructions for Formatting Your Assignments

Before attempting the assignments, please read the following instructions carefully.

1On top of the first page of your answer sheet, please write the details exactly in the following format:

ENROLMENT NO:….………………….………
NAME:…………..…………………

ADDRESS:.…...... ………………

………………………………

………………………………

COURSE CODE : …...... …………

COURSE TITLE : …...... …………

ASSIGNMENT NO.: …...... …………

STUDY CENTRE : …...... ………… DATE:..………………………….

(NAME AND CODE)

PLEASE FOLLOW THE ABOVE FORMAT STRICTLY TO FACILITATE EVALUATION AND TO AVOID DELAY.

2Use only foolscap size writing paper (but not of very thin variety) for writing your answers.

3Leave 4 cm margin on the left, top and bottom of your answer sheet.

4Your answers should be precise.

5While writing answers, clearly indicate the Question No. and part of the question being solved.

6Please note that:

i)Last date for submission of Assignment is March 31, 2011.

ii)The response to this assignment is to be submitted to the Study Centre Coordinator within eight weeks of the receipt of this booklet in order to get the feedback and comments on the evaluated assignment.

iii)In any case, you have to submit the assignment response before appearing in the term end examination.

7.We strongly suggest that you should retain a copy of your assignment responses.

Wishing you all good luck.

TUTOR MARKED ASSIGNMENT

Organic Chemistry

Course Code: CHE-5

Assignment Code: CHE-5/TMA/2010-11

Maximum Marks: 100

Note:* This assignment is based on all the four Blocks of the entire course.

* All questions are compulsory. Marks for the questions are shown within brackets on the right hand side.

* Please answer in your own words; do not copy from the course material.

  1. a) Give the IUPAC names of the following compounds:

(3)

b) Write the structures for the following compounds:

i)4-chloro-1-nitro-2-propylbenzene

ii)Ethyl 4-oxopentanoate(2)

  1. a) Assign configuration to the following compounds:

(3)

b)Give the IUPAC names of the compounds given in Q.2a).(2)

  1. Explain the following terms by giving suitable examples:

i)Flagpole hydrogens

ii)Ring flipping

iii)Racemate

iv)Enantiomer

v)Diastereomers(5)

  1. a) Which of the compounds in the following pairs will be more soluble in water and why?

i)Ethanol or hexanol

ii)Diethyl ether or pentane (3)

b)What is ‘finger print region’? How is it useful?(2)

  1. a) Arrange the following in the decreasing order of their pKa values and give reason for

your answer.

i)Ethanoic acid

ii)Propanoic acid

iii)Chloroethanoic acid

iv)Fluoroethanoic acid(5)

  1. a) What is octane number? Give the octane number of the following:

i)1: 1 mixture of iso-octane and n-heptane

ii)Gasoline (Premium)(2)

b)Give any one example of the following:

i)Wurtz reaction

ii)Nitration of alkane

iii)Isomerisationof alkanes(3)

  1. a) Draw themolecular orbital picture of alkane.(1)

b)Write the mechanism of Wittig reaction.(2)

c)Complete the following reactions:

(2)

  1. a) Give the reaction condition(s) of the following reactions:

(2)

b)Arrange the following in the increasing order of acidity:

(1)

c)How will you prepare

i)hexyne from ethyne?

ii)an alkyne from an alkane?(2)

  1. a) State Huckel’s rule. (1)

b)Write the resonance structures of the carbocation formed during the nitration of phenol.(2)

c)Give the mechanism of Friedel-Craft’s alkylation of naphthalene. (2)

  1. a) Write the structure of 1,3-oxole and 1,2-diazine.(2)

b)Write any one source of each of the following:

i)Thiophene

ii)Pyrrole(1)

c)Complete the following reactions:

(2)

  1. Explain with suitable examples:

a)Both chlorobenzeneand chloroethene do not undergo substitution reactions under ordinary conditions with NaOH.

b)Carbonyl group of benzaldehyde isless reactive towards nucleophilic addition reactions than the carbonyl group of ethanal.

  1. Write the product (s) and mechanism for the following reactions:

(5)

  1. How would you carry out following conversions?

a)Ethene to oxirane

b)Benzylmagnesiumchloride to 3-phenylpropanol

c)Propene to glycerol

d)Benzaldehydeto 3-phenylpropenoic acid

e)Ethanol to trichloromethane(5)

  1. a) How would you differentiate between differentclasses of alcohols?

b)Give two reduction methods which can convert a carbonyl compound to an alkane.

  1. How will you prepare the following?

i)2- Methylbutanoic acid from 2-chlorobutane

ii)Chloramine-T from 4-methylbenzenesulphonic acid(5)

  1. Explain the following reactions giving suitable examples: (5)

i)Reformatsky reaction

ii)Strecker synthesis(5)

  1. Complete the following reactions:

i)CH3COCl + HOCH2CH2CH3

iii)Benzene + ethanoic anhydride ...... +......

(5)

  1. Discuss the reduction of nitrobenzene under different conditions.(5)
  2. i)Discuss the IR and mass spectral characteristics of primary aliphatic amines.(2)

ii)How are primary amines synthesised using Curtiusrearrangement?(3)

  1. Draw the structures and give names of the four nucleotides presentin DNA and RNA.(5)

1