MES PONNANI COLLEGE
THIRD SEMESTER
SECOND INTERNAL EXAMINATION
CHEMISTRY COMPLEMENTARY COURSE
ORGANIC AND BIOCHEMISTRY
Time : 2.5 hours
Marks : 30
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Part A
Answer all questions. Each carries a weightage of ¼
Reaction of HBr to propene in the presence of peroxide is a/an
a) electrophilic addition
b) nucleophilic addition
c) free radical addition
d) none of these
Which is an ortho-para directing group?
a) –SO3H
b) –CN
c) –C2H5
d) –NO2
The only alpha-amino acid in which alpha-carbon is not an asymmetric carbon atom is
a) glycine
b) alanine
c) serine
d) cysteine
An ion containing both a positive and a negative charge is a/an
a) non-polar ion
b) zwitter ion
c) semi-polar ion
d) internal ion
The necessary condition for a substance to show optical isomerism is that its molecule should be
______
a) achiral
b) chiral
c) asymmetric
d) non-dissymetric
In the NMR spectrum of ethanol (CH3-CH2-OH), which kind of proton will show absorption at the
lowest field strength?
a) CH3
b) CH2
c) OH
d) all absorb at same field strength
The chief constituents of essential oils are _________
a) terpenes
b) alkaloids
c) steroids
d) esters
Citral on reduction with sodium amalgam in acetic acid gives ________
The monomer units of the condensation polymer nylon-66 are hexamethylene diamine and ____
Shift of absorption to a shorter wavelength is called a _______ shift.
The separation of a recemic mixture into its d and l components is called _______
The nitrating mixture helps the generation of the nucleophile ______ in the nitration of benzene.
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Part B
Answer all questions. Each carries a weightage of 1
What are electrophilic addition reactions? Give two examples.
How will you explain the low reactivity of chlorobenzene toeards SN reactions?
What is meant by Walden inversion?
What is meant by denaturation of a protein?
What are the different classes of enzymes?
What is meant by recimization?
What is meant by spin-spin splitting? Illustrate taking the case of ethanol.
Draw the structure of isoprene and state isoprene rule.
Draw the geometrical isomers of citral.
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Part C
Answer 5 questions. Each carries a weightage of 2
State and explain Huckel’s (4n+2) rule of aromaticity?
Discuss E1 and E2 mechanism of elimination reactions.
Discuss the principle and application of IR spectroscopy.
Give a few colour tests for protein
Discuss the structural features of DNA. Compare the functions of DNA and RNA.
Discuss i) the biochemical method; and ii) the chemical method for the resolution of racemic
mixture.
How are alkaloids extracted from their natural sources? How are they purified?
Part D
Answer 2 questions. Each carries a weightage of 4
a) Describe with theory the capillary rise method of determining surface tension of a liquid.
b) What is optical exaltation? Explain.
Discuss in detail the optical isomerism of tartaric acid.
a) What is the principle of NMR spectroscopy?
b) How will you differentiate the two isomers of C2H6O using NMR spectroscopy?