Identify the alkyne in the following sequence of reactions,Alkyne

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 Multiple Choice QuestionsMultiple Choice Questions

31.

A and B respectively are

  • Both 

  • Both 


32.

Which of the following compounds cannot be prepared singly by the Wurtz reaction?

  • C2H6

  • (CH3)2CHCH3

  • CH3CH2CH2CH3

  • All of the above can be prepared


33.

The product Y is

  • p-chloro nitrobenzene

  • o-chloro nitrobenzene

  • m-chloro nitrobenzene

  • o, p-dichloro nitrobenzene


34.

End product of the following reaction is


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35.

Which of the following conformers for ethylene glycol is most stable?


36.

The IUPAC name of the compound CH3CH=CHCCH is is

  • pent-4-yn-2-ene

  • pent-3-en-1-yne

  • pent-2-en-4-yne

  • pent-1-yn-3-ene


37.

Consider the reactions,

(CH3)2CH-CH2Br C2H5OH(CH3)2CH-CH2OC2H5 + HBr(CH3)2CH-CH2Br C2H5O-(CH3)2CH-CH2OC2H5 + Br-

The mechanisms of reactions (i) and (ii) are respectively

  • S1 and SN2

  • SN 1 and SN1

  • SN 2 and SN 2

  • SN 2 and SN1


38.

CH3CH2Br undergoes Wurtz reaction. We may expect some of the following product

A: CH3CH2CH2CH3

B: CH2=CH2

C: CH3-CH3

Select correct product.

  • Only A

  • A and B

  • A, B and C

  • A and C


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39.

Identify the alkyne in the following sequence of reactions,

Alkyne Lindlar's catalystH2A Ozonolysis B only                                                   Wacker processCH2=CH2

  • H3C-CC-CH3

  •  H3C-CH2-CCH 

  • H2C=CH-CCH 

  • HCC-CH2-CCH


A.

H3C-CC-CH3

In Wacker process, alkene is oxidised into aldehyde.

CH2=CH2 + 12O2 H2OPdCl2·CuCl2 CH3CHO(B)

Since on ozonolysis, only alkenes produce aldehydes, 'A' must be an alkene. To decide the structure of alkene that undergoes ozonolysis, bring the products together in such a way that O atoms are face to face and, replace O by double (=) bond. Thus,


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40.

CH3CH3 + HNO3 675K ?

  • CH3CH2NO2

  • CH3CH2NO2 + CH3NO2

  • 2CH3NO2

  • CH2= CH2


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