The relative reactivities of acyl compounds towards nucleophilic

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 Multiple Choice QuestionsMultiple Choice Questions

211.

1-butyne on oxidation with hot alkaline KMnO4 would yield. Which of the following as end product?

  • CH3CH2CH2COOH

  • CH3CH2COOH

  • CH3CH2CH2COOH + CO2 + H2O

  • CH3CH2CH2COOH + HCOOH


212.

 A cubic unit cell of a metal with a molar mass of 63.55 g mol-1 has an edge length of 362 pm. Its density is 8.92 g cm-3. The type of unit cell is

  • Primitive

  • Face centred

  • End centred

  • Body Centred


213.

Which of the following is the major product in the reaction of HOBr with propene?

  • 2-bromo, 1-propanol

  • 3-bromo,1-propanol

  • 2-bromo, 2-propanol

  • 1-bromo, 2-propanol


214.

Which of the following is the correct IUPAC name?

  • 3,4 -dimethyl pentanoyl chloride

  • 1-chloro-1-oxo-2, 3-dimethyl pentane

  • 2-ethyl-3-methyl butanoyl chloride

  • 2,3-dimethyl pentanoyl chloride


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215.

The pair of boiling point and compound are given as,

C6H(80°C); CH3OH (65°C); C6H5NO2 (212°C) and C6H5NH2 (184°C)

Which will show lowest vapour pressure at room temperature?

  • C6H6

  • CH3OH

  • C6H5NO2

  • C6H5NH2


216.

In the following conversion,

Identify 'A' from the following option

  • NaBD4

  • LiAID4

  • Mg, ether/D2O

  • BH3, D2O


217.

Ethers like ROR can be cleaved by concentrated HI but not by HCl because

  • I- is a weaker nucleophile than Cl-

  • I- is stronger nucleophile than Cl-

  • SN1 mechanism carried out in this reaction is rapidly in presence of HI.

  • None of the above


218.

Consider the following reaction sequence

CH3OH HBr 'A' KCN 'B' H2/ Ni 'C' HNO2 'D'

Choose the correct option regarding the different products obtained in the above reaction sequence:

  • 'D' is an alcohol consisting one carbon more than the starting alcohol

  • Product 'B' is formed via SN2-pathway

  • 'C' is an amine

  • All of the above


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219.

The relative reactivities of acyl compounds towards nucleophilic substitution are in the order of

  • acyl chloride > acid anhydride > ester > amide

  • ester > acyl chloride > amide > acid anhydride

  • acid anhydride > amide > ester > acyl chloride

  • acyl chloride> ester> acid anhydride > amide


A.

acyl chloride > acid anhydride > ester > amide

Nucleophilic substitution reaction is a class of reaction in which an electron rich nucleophile selectively bonds with or attacks the positive or partially positive charge of an atom or a group of atoms to replace a leaving group. The ease of nucleophilic substitution depends upon the nature of leaving group. When the leaving tendency of a group in a compound is high, then the compound is more reactive towards nucleophilic substitution. The nucleophilic acyl substitution is completed in two steps as shown below

The reactivity of the compound may be explained on the basicity of the leaving group. A weaker base is a better leaving group. The basicity order is as

CI- > RCOO- >RO- >NH2-

Hence, the order of the leaving tendency is

Cl- > RCOO- > R-O- > NH2- 

and therefore, the order of reactivity of acyl compound is as

Acyl chloride > Acid anhydride > Ester> Amide


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220.

The suitable reaction steps to carry out the following transformation is

  • (ii) H2O2, NaOH(i) BH3, THF HIO4

  • (CH3)3C.COOH, OH-OsO4 H2OK3Cr2O7.H2SO4

  • (ii) H2O2, NaOH(i) BH3, THF CH2Cl2PCC

  • H2O, H2SO4 (dil) CH2Cl2PCC


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