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Question:

(1) C_6H_5-O||C-C_6H_5 (2) C_6H_5-CHO (3) p-CH_3-C_6H_4-CHO (4) p-CH_3O-C_6H_4-CHO Correct order for nucleophilic addition reaction.

2>1>3>4

4>3>2>1

2>3>4>1

4>2>3>1

Solution:

Correct option is C. 2>3>4>1
Reactivity of carbonyl compounds towards nucleophilic addition reaction depends on the presence of substituted group. Aldehydes are more reactive than ketone for nucleophilic addition reaction. Electron withdrawing (-I, -M group) increased reactivity towards nucleophilic addition reaction. As the -OCH3 and CH3 groups shows +R and +I effect hence the reactivity decreases. Thus the correct order is- 2>3>4>1