For reaction $\mathrm{RX}+\mathrm{OH}^{-} \rightarrow \mathrm{ROH}+\mathrm{X}^{-}$, Rate expression is…
For reaction $\mathrm{RX}+\mathrm{OH}^{-} \rightarrow \mathrm{ROH}+\mathrm{X}^{-}$, Rate expression is $\mathrm{R}=4.7 \times 10^{-5}[\mathrm{RX}]\left[\mathrm{OH}^{-}\right]+2.4 \times 10^{-5}[\mathrm{RX}]$. What $\%$ of reactant react by $S N^2$ mechanism when $\left[\mathrm{OH}^{-}\right]=0.001$ molar -
0.195
66.2
95.1
16.4
Solution
Fraction of reactant decomposing
by $\mathrm{S}_{\mathrm{N}} 2$ mechanism
$=\frac{4.7 \times 10^{-5}[\mathrm{RX}]\left[\mathrm{OH}^{-}\right]}{4.7 \times 10^{-5}[\mathrm{RX}]\left[\mathrm{OH}^{-}\right]+2.4 \times 10^{-5}[\mathrm{RX}]}$
Put $\left[\mathrm{OH}^{-}\right]=0.001 \mathrm{M}$