The increasing order of the rate of HCN addition to compounds A – D is (i) HCHO (ii) CH_3-CO-CH_3 (iii) PhCOCH_3 (iv) PhCOPh

MHT CET Chemistry question

The increasing order of the rate of HCN addition to compounds A – D is (i) HCHO (ii) (iii) (iv)

(A)(i) < (ii) < (iii) < (iv)
(B)(iv) < (ii) < (iii) < (i)
(C)(iv) < (iii) < (ii) < (i)Correct
(D)(iii) < (iv) < (ii) < (i)

Answer: (C)

Solution

Addition of HCN is faster for the less hindered, more electrophilic carbonyl: HCHO > acetone > acetophenone > benzophenone (phenyl groups add steric hindrance

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Question ID VK-081427