Question

Consider the following reaction and choose the correct option:

• A. Rate of reaction I remain unchanged if concentration of $O{H}^{-}$ increases
• B. Rate of reaction II remain unchanged if concentration of $O{H}^{-}$ increases.
• C. Rate of both reactions become double if concentration of $O{H}^{-}$ become double
• D. Rate of both reations do not depend upon concentration of $O{H}^{-}$

Answer 1

The correct option is A Rate of reaction I remain unchanged if concentration of $O{H}^{-}$ increases

First reaction is $S{N}_1$ i.e. first order in which rate does not depend on concentration of nucleophile.
Second reaction is $E_2$ reaction in which rate depends on concentration of substrate and base both because it is a second order reaction; first order with respect to each of substrate and base.
So, by doubling the conentration of $O{H}^{-}$, rate of reaction I does not change.
Hence, (a) is the correct option.