Discussion Forum



1)

Which of the following is most reactive towards the addition reaction of hydrogen cyanide to form the corresponding cyanohydrin?


A) Acetone

B) Formaldehyde

C) Acetaldehyde

D) Diethylketone

Answer:

Option B

Explanation:

Formaldehyde (HCHO) is most reactive towards the addition reaction of hydrogen cyanide because it is least sterically hindered.

1562021829_c4.PNG

 The order of reactivity towards  addition of hydrogen cyanide is a follows:

1562021346_c5.PNG

 Note: In case of ketones, only  acetone, butanone , pentan-3-one and pinacolone form cyanohydrin .The failure with bulky ketones is largely  due to steric  effects.