Question

The correct order of rate of reaction toward nucleophilic addition reaction.

• A. a > b > c > d > e
• B. a > b > d > c > e
• C. a > d > e > b > c
• D. a > b > e > d > c

Answer 1

The correct option is A a > b > c > d > e

Aldehydes are more reactive towards nucleophilic substitution compared to ketones because of less steric hindrance and electronic factors. In Aldehydes electron withdrawing group increase its reactivity by making the carbonyl carbon more electrophilic.
So, a,b,c are more reative than d and e
Rate towards Nucleophilic addition is high when electron density is low at carbonyl carbon. So, the groups attached should be electron withdrawing groups.
$-N{O}_2$ is an electron withdrawing group whereas $-OMe$ is an electron donating group
So the order of reactivity for aldehydes is:
a>b>c
Between the ketones d and e
Rate of nucleophilic reaction is less in e because two bulky groups (benzene rings) attached which makes it difficult for a nuclephile to attack.
Correct order is:
$\Rightarrow a>b>c>d>e$