Download CHE-05 Organic Chemistry

CHE-05
Assignment Booklet
Bachelor’s Degree Programme (B. Sc.)
Organic Chemistry
CHE-05
School of Sciences
Indira Gandhi National Open University
New Delhi, 110068
2006
1
Dear Student,
We hope, you are familiar with the system of evaluation to be followed for the Bachelor's
Degree Programme. As 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 two
tutor-marked assignments for this course. These assignments are provided in this booklet.
Assignment-01 is based on Blocks 1 and 2 whereas Assignment-02 is based on Blocks 3 and 4.
Instructions for Formatting Your Assignments
Before attempting the assignments, please read the following instructions carefully.
1.
On 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.
2.
3.
4.
5.
Use only foolscap size writing paper (but not of very thin variety) for writing your answers.
Leave 4 cm margin on the left, top and bottom of your answer sheet.
Your answers should be precise.
While writing answers, clearly indicate the Question No. and part of the question being
solved.
Assignment No.
Assignment – 1 (TMA)
Assignment – 2 (TMA)
Submission
Where to Send
6 weeks after receiving the print coordinator of your study
material with assignments.
centre
10 weeks after receiving the print coordinator of your study
material with assignments.
centre
6. We strongly suggest that you should retain a copy of your assignment responses.
Wishing you all good luck.
2
Assignment - 01
Tutor Marked Assignment
Organic Chemistry
Course Code: CHE-05
Assignment Code: CHE-05/TMA-01/2006
Maximum Marks: 100
Answer all the questions given below.
Q.1. (a)
Give the IUPAC names of the following compounds:
(6)
H OH
(i)
H3C  C  C  CH3
CH3 H
(ii)
HC  CCH2CH2OH
NH2
(iii) CH3  CH2  (CH2)4  CH  COOH
(b)
Write the structural formulae for the following compounds:
(i)
(ii)
Q.2. (a)
p - Methoxybenzyl alcohol
4 - Bromo -N - ethyl - N - methylpentanamide
Assign the configuration as E or Z to the following compounds:
Cl
i)
COOH
C = C
Q.3. (a)
Cl
ii)
CH3
(b)
(4)
(5)
CH2OH
C= C
CH3
Br
H
Write the stereoisomers of 2 - butanol and designate them as diastereomers and
enantiomers.
(5)
Assign the configuration as R or S to the following compounds:
(5)
H
i)
CH3CH2
H
Br
ii)
C  CH
H2N
CH3
CH3
3
(b)
Identify which of the following Fischer projections are identical? Give reason in
support of your answer.
CHO
Cl
Cl
H
HO
OH
(I)
Q.4. (a)
H
CHO
OHC
H
(II)
(5)
OH
OH
Cl
Cl
(III)
CHO
H
(IV)
Give reason why
(6)
(i) is  - carotene red - orange in colour?
(ii) 1, 3 - butadiene has higher  max value than ethene?
(iii) (M+1) and (M+2) peaks appear in the mass spectrum of organic compounds?
(b)
Identify the chemically equivalent protons in the following compounds:
Cl
(i)
Q.5. (a)
(ii)
CH3CH2CCH2CH3
(10)
2  Hydroxybenzenecarboxylic acid is more acidic than benzenecarboxylic acid.
A tertiary carbocation is more stable than a primary carbocation.
Aniline is less basic than ammonia.
The pKa of monochloroethanoic acid is less than that of ethanoic acid.
Give the appropriate composition of the following:
(i)
(ii)
(iii)
(iv)
(b)
O
Explain the following:
(i)
(ii)
(iii)
(iv)
Q.6. (a)
CH3CH  CH2Cl
(4)
(2)
Natural gas
Light petrol
Paraffin wax
Lubricating oil
How would you prepare alkanes from the following: (Give only one example)
(3)
(i) Alky lhalide
(ii) Carboxylic acid
(iii) Alkene
(c)
Explain the following:
(3)
(i) The UV spectroscopy is not of much help in characterisation of alkanes.
(ii) In the mass spectra, alkanes give a series of peaks separated by 14 mass units.
(iii) Alkanes with odd number of carbon atoms have lower melting point than those with
an even number of carbon atoms
(d)
Complete the following reactions:
(2)
(i)
CuO .Cr O3
CH3CH2COOH + C5H5N 2
 ……….
(ii)
 …………….
BrCH2CH2CH2Br + 
4
Q.7. (a)
(b)
What is difference between cumulated diene and conjugated diene ? Explain
(3)
Explain the following in one to two lines.
(2)
(i)
(ii)
(c)
Fill in the following blanks:
(i)
(ii)
(d)
Q.8. (a)
Alkenes are more soluble in water than corresponding alkanes.
Addition reactions of alkenes are exothermic processes.
(2)
In the UV spectrum, the ethylenic chromophore shows an absorption
band below --------- nm.
In the IR spectrum, the cis isomer of internal alkenes gives band at ------ cm1.
Complete the following reactions:
(3)
1. O
3  ……………………..
2. H 2 O/Zn
(i)
CH 3 CH 2 CH 2 CH  CHCH3
ii)
iii)
CH3COOH
CH3CH2BH2 

 …………………………………
 …………………
CH2 = CH – CH = CH2 + CH2 = CH2 
Answer the following briefly.
(3)
(i)
How would you differentiate terminal alkyne and internal alkyne by NMR
spectrum?
(ii) What is the difference in absorption pattern of terminal and internal alkynes
in their IR spectra?
(iii) Why physical constants of alkynes increase with increase in molecular weight?
(b)
Alkene is more acidic than alkane. Explain.
(3)
(c)
How would you carry out the following:
(4)
(i)
(ii)
(iii)
(iv)
Q.9. (a)
Explain the following:
(i)
(ii)
(b)
3-Octyne from 1 – hexyne
1,2-Dibromoethene from ethyne
Ethanal from ethyne
cis-3-Hexene from 3-hexyne
(2)
Absorption in region of 1225-970 cm1 in IR spectra is not very useful for
identification of aromatic compounds.
The theoretical value of heat evolved, when hydrogens are added to benzene,
is quite high as compare to the experimental value.
What is Huckel’s rule? Which of the following compound(s) is aromatic?
Justify your answer.
(i)
(ii)
Cycloctatetraene
Nitrobenzene
5
(3)
(c)
Complete the following reactions:
(i)
(ii)
(3)
AICI 2
 …………
C6H6 + (CH3)2CHCl  
h

C H – CH + Cl 
 ……………
6
5
3
2
KMnO4
(iii) C6H5 – CH3 
 …………………
(d)
Q.10. (a)
Write all the possible resonance structures of cation formed from ortho
nitration of methyl benzene.
(2)
Write the structure of the following compounds:
(2)
(i)
(ii)
3-Methyl-1,3-thiozol
2-Amino-1,4-diazine
(b)
Draw the orbital picture of furan and pyridine.
(c)
Explain the following:
(i)
(ii)
(d)
(2)
(22)
2-Position in furan is more reactive than the 3-position towards electrophelic
substitution.
Pyrrole is more basic than pyridine.
Complete the following reactions:
 ………..
(i) 2 CH3 CHO + HCHO 
675 K
(ii) CH2= CHCH = CH2 + 2 S 

6
(2)
Assignment – 02
Tutor Marked Assignment
Organic Chemistry
Elective Course in Chemistry
Course Code : CHE-05
Assignment Code : CHE-05/TMA-02/2006
Maximum Marks : 100
Answer all the questions given below.
Q.1. (a)
(b)
Q.2. (a)
(b)
Taking a suitable example write the mechanism of SN1 reaction. Explain the
effect of the structure of alkyl halides over the reaction rate.
(5)
Explain why allylic and benzylic halides very reactive under SN1
condition?
(5)
Complete following reactions:
(4)
HgCl 2
(i)
ethyne  HCl
(ii)
Ar  NH 2
(iii)
CHCl 3  RNH 2 KOH
 ………………………………….
(iv)
(CH 3 ) 2 C  CH 2
 …………………………………..
373  473 K
(i) NaNO 2 / HCl, Cold
 …………………………….
(ii ) CuCl / HCl
(i ) B 2 H 6
 ………………………..
(ii ) H 2 O 2 , NaOH
Explain the following:
(6)
p – Nitrophenol has higher boiling point and solubility in water
than o – nitrophenol.
(ii) Oxirane are more reactive than open chain ethers.
(iii) Phenols are acidic in character, while alcohols are almost neutral.
(i)
Q.3. How would you prepare the following?
(i)
(ii)
(iii)
(iv)
(v)
Q.4. (a)
(10)
1,2 – benzenediol from salicylaldehyde
Trichloromethane from ethanol
Phenol from chlorobenzene
Phanolphthalein from phenol
1,2,3 – propanetriol from propene
Explain why sulphur analogues of alcohols and ethers are more nucleophilic?
(2)
(b)
Give the simple laboratory method of detection of carbonyl group in an organic
(3)
compound. Name the simple test used to distinguish between aldelydes and ketones.
(c)
How would you carry the following conversions?
(i)
(ii)
Ketone to alkane
Ketone to alcohol
7
(5)
Q.5. (a)
(b)
What is mixed aldol condensation? Write the mechanism of the reaction.
(4)
Give reaction for the following change
(6)
(i) propanone to 2 –methylpropene
(ii) ethanal to 2-butenal
(iii) benzaldehyde to malachite green
Q.6. (a)
Discuss one method each for the synthesis of the carboxylic acids having
(i)
(ii)
(b)
Q.7. (a)
one carbon atom less than the starting material.
one carbon atom more than the starting material.
How are carboxylic acids identified using
(i) IR spectrum?
(ii) NMR spectrum?
(5)
How will you convert
(10)
(i)
(ii)
(iii)
(iv)
propanone to 2 - methyl - 2 - hydroxypropanoic acid?
naphthalene to 1,2 - benzenedicarboxylic acid?
ketene to ethanoic anhydride?
ethyl ethanoate to 3-ethyl -3- pentanol?
Q.8. Explain the following name reactions:
(i)
(ii)
(iii)
(iv)
Q.9. (a)
(5)
(10)
Knoevenagel condensation
Strecker synthesis
Rosenmund reduction
Henry reaction
Give two important uses of nitro compounds.
(2)
(b)
How will you distinguish primary, secondary and tertiary amines in the
laboratory?
(3)
(c)
What is mutarotation? Explain.
(3)
(d)
How will you prepare butter yellow?
(2)
Complete the following reactions:
(6)
Q.10. (a)
Na 2 Cr2 O 7
…………………………………….
aniline
(ii)
 ……………………………
benzaldehyde + nitromethane 
H 2 SO 4 , 283 K
(iii) ethyl pentanoate
(iv)
(b)

(i)
Na

……………… + ………………..

423 K
………………... + ……………….
alcohol
propanedioic acid

Give one example each for the following classes of compounds:
(i)
alkaloids
(ii) terpenes
(iii) steroids
8
(iv) disaccharides
(4)