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# NEET Chemistry Solved Question Paper 2013

#### Multiple Choice Questions

51.

Which of the following aldoses gives an optically active compound upon reaction with warm dilute nitric acid ?

C.

Only compound (c) will give an optically active compound upon reaction with warm dilute HNO3 , while other will give meso diacids.

52.

During dehydration of alcohols to alkenes by heating with conc. H2SO, the initial step is :

• formation of an este

• protonation of alcohol molecule

• formation of carbocation

• elimination of water

B.

protonation of alcohol molecule

The initial step during dehydration of alcohols is protonation of the alcohol molecule.

53.

CH3CHO $\stackrel{\mathrm{Oxidation}}{\to }$ (A0 $\stackrel{{\mathrm{PCl}}_{5}}{\to }$ (B) $\stackrel{{\mathrm{CH}}_{3}\mathrm{COONa}}{\to }$ (c) .Compond (C) is :

• (CH3CO)2O

• CH3COCH3

• CH3COOCH3

• CH3COOC2H5

A.

(CH3CO)2O

CH3CHO $\stackrel{\mathrm{Oxidation}}{\to }$ CH3COOH $\stackrel{{\mathrm{PCl}}_{5}}{\to }$ CH3COCl $\stackrel{{\mathrm{CH}}_{3}\mathrm{COONa}}{\to }$ (CH3CO)2O

54.

Phenol , when it first react with cone. sulphuric acid and then with cone. nitric acid gives :

• nitrobenzene

• 2 , 4 , 6 - trinitrobenzene

• o - nitrophenol

• p - nitrophenol

C.

o - nitrophenol

-SO3H groups are knocked out on boiling with H2O.

55.

By adding sodium dodecyl sulphate, during the electrophoresis of proteins, it is possible to :

• determine a protein's isoelectric point

• determine an enzyme's specific activity

• determine the amino acid composition of the protein

• presence a proteins native structure and biological activity

D.

presence a proteins native structure and biological activity

Adding sodium dodecyl sulphate during electrophoresis of amino acids preserve the proteins native structure and biological activity .

56.

In the $\mathrm{\alpha }$-helix , the hydrogen bonds

• are roughly parallel to the axis of the helix

• are roughly perpendicular to the axis of the helix

• occur mainly between electronegative atoms of the R groups

• occur only between some of the amino acids of the helix

A.

are roughly parallel to the axis of the helix

In a-helix structure, H-bonds are parallel to the axis of helix

57.

The strongest acid among the following compound is :

• HCOOH

• CH3CH2CH(Cl)COOH

• ClCH2CH2CH2COOH

• CH3COOH

B.

CH3CH2CH(Cl)COOH

CH3CH2CH(Cl)COOH is the strongest acid due to the presence of strong electron withdrawing group Cl at a carbon atom.

# 58.Which ofthe following is true regarding teflon ?It is a linear, unbranched polymer of tetrafluoro ethylene It has very high thermal stability Polymer molecules are associated by strong dipole-dipole attraction All of the above

D.

All of the above

Due to symmetry of F2C = CF2 and strength of C-F bond , branching does not take place and a linear chain teflon is always formed. High bond energy of C-F bond gives high thermal stability to polymer . Large electronegativity difference of 'C' and F makes C-F bond highly polar.

59.

Cellulose has very high degree of hydrophilicity because of :

• its amorphous nature

• crystalline nature

• presence of excessive voids in solid state

• presence of many hydroxyl groups on the polymer back bone

D.

presence of many hydroxyl groups on the polymer back bone

Cellulose is a polyhydroxy compound, contain several free hydroxyl groups ion its back bone capable of forming intermolecular H-bonds with water .

60.

Which one ofthe following antioxidant commonly used to increase the storage life of butter ?

• Butylated hydroxy anisol

• Sodium sulphite

• Sodium metabisulphite

• All of the above

A.

Butylated hydroxy anisol

Butylated hydroxy anisole increases the storage life of butter from months to years .