Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

41.

Consider the nitration of benzene using mixed conc. H2SO4 and HNO3. If a large amount of KHSO4 is added to the mixture, the rate of nitration will be

  • slower

  • uncharge

  • doubled

  • doubled


A.

slower

IN the nitration of benzene in the presence of conc. H2SO4 and HNO3, benzene is formed.
HNO3 +H2SO4 rightwards harpoon over leftwards harpoon space NO subscript 2 superscript plus space plus HSO subscript 4 superscript minus space plus straight H subscript 2 straight O
If a large amount of KHSO4 is added to this mixture more HSO4- ion furnishes and hence the concentration of electrophile decreases, rate of electrophilic aromatic reaction slows down.

2354 Views

42.

The product formed by the reaction of an aldehyde with a primary amine is

  • Ketone

  • Carboxylic acid

  • Aromatic acid

  • Aromatic acid


D.

Aromatic acid

1442 Views

43.

The correct statement regarding RNA and DNA, respectively is

  • The sugar component in RNA is ribose and sugar component in DNA is 2' deoxyribose

  • The sugar component in RNA is arabinose and the sugar component in DNA is ribose

  • The sugar component in RNA is 2'-deoxyribose and the sugar component in DNA is arabinose

  • The sugar component in RNA is 2'-deoxyribose and the sugar component in DNA is arabinose


A.

The sugar component in RNA is ribose and sugar component in DNA is 2' deoxyribose

In DNA, two helically twisted strands connected together by steps. Each strand consists of alternating molecules of deoxyribose at 2'-position and phosphate groups. 
On another hand, in RNA, the pentose sugar has an identical structure with deoxyribose sugar except that there is an -OH group instead of -H on carbon atom2'. Hence it is only called ribose.

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44.

Which one given below is a non - reducing sugar?

  • Lactose

  • Glucose

  • Sucrose

  • Sucrose


C.

Sucrose

sucrose is non-reducing sugar because it has one -CHO group.

1193 Views

45.

In the reaction,

straight H minus straight C identical to CH space rightwards arrow from left parenthesis ii right parenthesis space CH subscript 3 CH subscript 2 Br to left parenthesis straight i right parenthesis space NaNH subscript 2 divided by liq. NH subscript 3 of space straight X
space space space space space space space space space space space space space space space space space space straight X space rightwards arrow from left parenthesis ii right parenthesis space CH subscript 3 CH subscript 2 Br to left parenthesis straight i right parenthesis NaNH subscript 2 divided by liq. NH subscript 3 of space straight Y
X and Y are

  • X=2-butyne; Y= 3-hexyne

  • X=2-butyne;Y=2-hexyne

  • X=1-butyne ;Y = 2-hexyne

  • X=1-butyne ;Y = 2-hexyne


D.

X=1-butyne ;Y = 2-hexyne

NaNH2/liq.NH3 behaves as a base, so it abstracts a proton from acetylene to form acetylide anion followed by alkylation to give compound (X) i.e 1-butyne (X) further reacts with NaNH2/Liq NH3 followed by alkylation with ethyl bromide yields 3-hexyne (Y).

straight H minus straight C identical to straight C minus straight H left parenthesis 1 right parenthesis space rightwards arrow with NaNH subscript 2 divided by liq. space NH subscript 3 on top space straight H minus straight C identical to straight C to the power of minus

straight H minus straight C identical to straight C to the power of minus rightwards arrow with stack CH subscript 3 minus CH subscript 2 minus Br with alkylation below on top space stack straight H minus straight C identical to straight C minus CH subscript 2 CH subscript 3 with bold X with bold 1 bold minus bold butyne below space below

stack straight H minus straight C identical to straight C minus CH subscript 2 CH subscript 3 with bold X with bold 1 bold minus bold butyne below space below space rightwards arrow with left parenthesis straight i right parenthesis space NaNH subscript 2 divided by liq. NH subscript 3 on top space CH subscript 3 CH subscript 2 minus straight C identical to straight C to the power of minus
stack CH subscript 3 CH subscript 2 minus straight C identical to straight C to the power of minus rightwards arrow with CH subscript 3 CH subscript 2 minus Br on top space straight H subscript 3 CCH subscript 2 minus straight C identical to straight C minus CH subscript 2 CH subscript 3 space with stack bold left parenthesis bold Y bold right parenthesis with bold 3 bold minus bold hexyne below below plus HBr

2672 Views