Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

41.

The human body does not produce:

  • DNA

  • Vitamins

  • Hormones

  • Hormones


B.

Vitamins

The organic compounds other than carbohydrates proteins, which maintain normal growth and nutrition in the human body (but not produced in the human body) are called vitamins.

628 Views

42.

Which one of the following is a peptide hormone?

  • Glucagon

  • Testosterone

  • Thyroxin

  • Thyroxin


A.

Glucagon

Glucagon is a peptide hormone because it is peptide linkage is present.

571 Views

43.

[NH(CH2)NHCO(CH2)4CO]n

  • co-polymer

  • addition polymer

  • thermosetting polymer

  • thermosetting polymer


A.

co-polymer

-[NH(CH)2NHCO(CH2)4CO]n- is a copolymer because polymers whose repeating structural units are derived from two or more types of monomer units are called copolymer.

space nH subscript 2 end subscript straight N space left parenthesis CH 2 right parenthesis NH subscript 2 end subscript space plus space nHOOC left parenthesis space CH subscript 2 right parenthesis subscript 4 COOH space rightwards arrow from nH subscript 2 straight O to Polymerisatiaon of
space minus open square brackets NH left parenthesis CH subscript 2 right parenthesis NHCO right parenthesis left parenthesis CH subscript 2 right parenthesis subscript 4 CO close square brackets subscript straight n minus

863 Views

44.

The major organic product in the reaction,

CH3 -O- CH(CH3)2 + HI → Product is:

  • CH3OH + (CH3)2 + CHI

  • ICH2OCH(CH3)2

  • CH3O CI(CH3)2

  • CH3O CI(CH3)2


D.

CH3O CI(CH3)2

CH subscript 3 minus straight O minus CH left parenthesis CH subscript 3 right parenthesis subscript 2 space plus space HI space rightwards arrow with 373 space straight K on top space straight H subscript 3 Cl space plus space left parenthesis CH subscript 3 right parenthesis CHOH
In the case of unsymmetrical ether, the alkyl halide is always formed from a smaller alkyl group. This happens so because I- ion being larger in size approaches smaller alkyl group to avoid steric hindrance.
554 Views

45.

Which of the following is more basic than aniline?

  • Diphenylamine

  • Triphenylamine

  • p-nitroaniline

  • p-nitroaniline


D.

p-nitroaniline

Benzylamine C6H5 - NH2 is more basic than aniline because benzyl group C6H5CH2 is electron donating group due to +I effect. So, it is able to increase the electron density of N of -NH2 group. Thus due to higher electron density rate of donation of a free pair of electron is increased i.e, basic character is higher. Phenyl and nitro group are electron attractive groups. so they are able to decrease the electron density of N of NH2 group. Hence, they are less basic with aniline.

997 Views

46.

During the process of digestion, the proteins present in food materials are hydrolysed in amino acids. The two enzymes involved in the process

Proteins space rightwards arrow with Enzyme space left parenthesis straight A right parenthesis on top space Polypeptides
space space space space space space space space space space space space space space rightwards arrow with Enzyme space left parenthesis straight B right parenthesis on top space Amino space acids comma
are respectively:

  • amylase and maltase

  • diastase and lipase

  • pepsin and trypsin

  • pepsin and trypsin


C.

pepsin and trypsin

In the process of digestion, the proteins present in food material are hydrolysed to an amino acid. In this process two enzymes pepsin and trypsin are involved as follows:

Proteins space rightwards arrow from left parenthesis Enzyme apostrophe straight A apostrophe to Pepsin of space Polypeptide rightwards arrow from left parenthesis Enzyme space apostrophe straight B apostrophe to Trypsin of space Amino space acid

786 Views

47.

A carbonyl compound reacts with hydrogen cyanide to form cyanohydrin which on hydrolysis forms a racemic mixture of alpha -hydroxy acid. The carbonyl compound is: 

  • CH3-CH2-CH2COCH3

  • (CH3)2C=O

  • CH3CH2CHO

  • CH3CH2CHO


D.

CH3CH2CHO



The carbonyl compounds undergo nucleophilic addition reaction because oxygen is more electronegative than carbon. As such, it withdraws share pi electron pair towards itself and gets a partial negative charge, therefore carbon gets a partial positive charge and becomes susceptible to nucleophilic attack.
The aldehyde is more reactive than ketones towards nucleophiles. This can be explained on the basis of inductive effect as well as steric effect. The addition of nucleophiles is based upon the positive charge present on a carbon atom of > C =O group.

In aldehyde >C=O group is present at least one alkyl group (except formaldehyde) which has +I effect (electron donating effect) and which decreases the positive charge of carbon, thereby making the attack to nucleophile difficult. The nucleophilic attack becomes more difficult in ketones having a minimum of two alkyl groups.
Hence, by means of attachment of alkyl groups (due to +I effect) rate of nucleophiles addition decreases.
Order of +I effect in an alkyl group.



order of nucleophilic addition in given carbonyl compound is 
CH3CHO > CH3-CH2- CHO > (CH3)2CO> CH3CH2CH2COCH3

567 Views

48.

Self-condensation of two moles of ethyl acetate in presence of sodium ethoxide yields

  • ethyl butyrate

  • acetoacetic ester

  • methyl acetoacetate

  • methyl acetoacetate


B.

acetoacetic ester

On condensation of two moles of ethyl acetate in presence of sodium ethoxide, gives ethyl acetoacetate (ester). This condensation is an example of claisen condensation because it is possible in that ester which has an alpha hydrogen atom.

1505 Views

49.

Ethylene oxide when treated with Grignard reagent yields:

  • Secondary alcohol

  • tertiary alcohol

  • cyclopropyl alcohol

  • cyclopropyl alcohol


D.

cyclopropyl alcohol

Ethylene oxide on treatment with a Grignard reagent to give an additive product which on hydrolysis to give primary alcohol as a final product.
 

825 Views

50.

A carbonyl compound reacts with hydrogen cyanide to form cyanohydrin which on hydrolysis forms a racemic mixture of alpha-hydroxy acid. The carbonyl compound is:

  • acetaldehyde

  • acetone

  • diethyl ketone

  • diethyl ketone


A.

acetaldehyde


If it is a racemic mixture, therefore such 'C' atom must be the asymmetric carbon atom.

1009 Views