Question

In the mechanism for cyanohydrin formation, why is HCN the acid that protonates the alkoxide ion, instead of HCl?

A)	HCl is a strong acid, so it decomposed completely.
B)	HCN is a weaker acid, so it dissociates completely and protonates the chloride ion.
C)	HCN is a weaker acid, so it dissociates completely and protonates the alkoxide ion.
D)	HCl is a strong acid, so it dissociates completely.
E)	HCl is a strong acid, so it dissociates completely and protonates the cyanide ion. Thus, there is no HCl in the reaction mixture.

Answer 1

Option E)HCl is a strong acid, so it dissociates completely and protonates the cyanide ion. Thus, there is no HCl in the reaction mixture.

is the correct answer to the question as weak acids cannot dissociates completely and HCl first protonates the Cyanide ion in the reaction.