Arrange the following compounds in incre | Class 12 Chemistry Chapter Aldehydes Ketones and Carboxylic Acids, Aldehydes Ketones and Carboxylic Acids NCERT Solutions

Question:

Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.

(i)Ethanal, Propanal, Propanone, Butanone.

(ii)Benzaldehyde, p-Tolualdehyde, p-Nitrobenzaldehyde, Acetophenone.

Hint:Consider steric effect and electronic effect.

Answer:

(i)

The +I effect of the alkyl group increases in the order:

Ethanal < Propanal < Propanone < Butanone

The electron density at the carbonyl carbon increases with the increase in the +I effect. As a result, the chances of attack by a nucleophile decrease. Hence, the increasing order of the reactivities of the given carbonyl compounds in nucleophilic addition reactions is:

Butanone < Propanone < Propanal < Ethanal

 

(ii)

The +I effect is more in ketone than in aldehyde. Hence, acetophenone is the least reactive in nucleophilic addition reactions. Among aldehydes, the +I effect is the highest in p-tolualdehyde because of the presence of the electron-donating -CHgroup and the lowest in p-nitrobezaldehyde because of the presence of the electron-withdrawing -NOgroup. Hence, the increasing order of the reactivities of the given compounds is:

Acetophenone < p-tolualdehyde < Benzaldehyde < p- Nitrobenzaldehyde
< p-Nitrobenzaldehyde


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Comments

  • sahil
  • 2019-09-26 20:04:58

awesome


  • Poonam
  • 2019-05-28 05:29:08

Very best g


  • Bhagavathi Manasa
  • 2018-09-16 19:47:10

It's good


  • Ankit raj
  • 2017-11-27 14:34:16

formaldehyde, propionaldehyde, isobutyraldehyde, acetone arrange in increasing reactivity in nucleophilic substance


Comment(s) on this Question

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 4: Arrange the following compounds in increasing order of their reactivity in nucleophilic addition rea....