Chemistry - Carbonyl compounds Question with Solution | TestHub

Question Explanation :

comparison of rate of haloform reaction with various halogens

Concept:

This question is based on Haloform reaction

Solution:

The rate of the haloform reaction is independent of the nature of the halogen ( ${\mathrm{X}}_2$ ) used. The rate-determining step in the basic-catalyzed haloform reaction is the formation of the enolate ion intermediate (or carbanion) by the abstraction of an $\alpha$-hydrogen by the base $\left({\mathrm{OH}}^{-}\right)$.

$\mathrm{R}-\mathrm{CO}-{\mathrm{CH}}_3+{\mathrm{OH}}^{-}\rightleftharpoons \mathrm{R}-\mathrm{CO}-{\mathrm{CH}}_2^{-}+{\mathrm{H}}_2\mathrm{O}$

Subsequent steps involving the halogenation of the carbanion are much faster than the initial deprotonation step. Therefore, the rate of the reaction depends only on the concentration of the substrate and the base, not on the specific halogen used.

Final Answer : Option (C)