Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple 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 Oxidation (A0 PCl5 (B) CH3COONa (c) .Compond (C) is :

  • (CH3CO)2O

  • CH3COCH3

  • CH3COOCH3

  • CH3COOC2H5


A.

(CH3CO)2O

CH3CHO Oxidation CH3COOH PCl5 CH3COCl CH3COONa (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.


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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 α-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.


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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.


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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 .


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