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 Multiple Choice QuestionsMultiple Choice Questions

271.

Amides are converted to amines by the following reaction :

  • Perkin

  • Claisen

  • Hofmann

  • Clemmensen


272.

N2 gas is liberated when [HCl + NaNO2] reacts with the following compound :

(A) CH3CH2NH2   (B) Urea

(C) CH3CONH2    (D) C6H5NH2

The answer is :

  • A , B , C

  • A , B , D

  • A, C , D

  • B , C , D


273.

Acetamide when heated with PCl5 gives :

  • CH3Cl

  • CH3CN

  • CH3CCl2NH2

  • CHCl2CONH2


274.

Which of the following reactions does not yield an amine?

  • R-X + NH3 

  • R-CH=NOH + [H] NaC2H5OH

  • R-CN +H2H+

  • R-CONH2 LiAlH4


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275.

The chemical name for melamine is

  • 1,3,5-Triamino-2,4,6-triazine

  • 2,4,6-Triamino-1,3,5-triazine

  • 2-Amino-1,3,5-triazine

  • 2,4-Diamino-1,3,5-triazine


276.

Bromine is added to cold dilute aqueous solution ofNaOH. The mixture is boiled. Which of the following statements is not true?

  • During the reaction bromine is present in four different oxidation states.

  • The greatest difference between the various oxidation states of bromine is 5.

  • On acidification ofthe final mixture bromine is formed.

  • Disproportionation of bromine occurs during the reaction.


277.

RNO2 is reduced with Sn/HCl .Product formed is :

  • RNHOH

  • RNH2

  • RNH3+

  • R2NH


278.

The compound which on reaction with aqueous nitrous acid at low temperature produces an oily nitrosoamine is

  • methyl amine

  • ethyl amine

  • diethyl amine

  • triethyl amine


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279.

Hofmann's bromamide reaction is used to convert :

  • acid to alcohol

  • alcohol to acid

  • amide to amine

  • amine to amide


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280.

Compound A (molecular formula C3H8O) is treated with acidified potassium dichromate to form a product B (molecular formula C3H6O). B forms a shining silver mirror on warming with ammoniacal silver nitrate. B when treated with an aqueous solution of H2NCONHNH2. HCl and sodium acetate gives a product C. Identify the structure of C.

  • CH3CH2CH=NNHCONH2

  • CH3-C(CH3)=NNHCONH2

  • CH3-C(CH3)=NCONHNH2

  • CH3CH2CH=NCONHNH2


A.

CH3CH2CH=NNHCONH2

A is an alchohol and its oxidation product gives Tollen's test.Tollen's reagents is a chemical reagents used to determine the presence of aldehyde, aromatic aldehyde, and alpha-hydroxyl ketone functional group. The reagent consists of a solution of sliver nitrate, ammonia and some sodium hydroxide.

C3H8OA  K2Cr2O7/ H+ C3H6OB amm. AgNO3 Silver mirror

Reaction of B indicates that B is an aldehyde thus B should be C2H5CHO or CH3CH2CHO and therefore C should be CH3CH2CH=NNHCONH2.

CH3CH2CH2OH[A] [O] CH3CH2CHO [B] Silver mirror testCH3CH2COOH + 2Ag

CH3CH2CH2OH + H2NNHCONH2semicarbazide  CH3CH2CH=NNHCONH2semicarbazone [C]


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