In a standard reaction obeying second-order kinetics, if the concentration of the alkyl halide subst — Reaction Mechanism Chemistry Question
Question
In a standard $S_N2$ reaction obeying second-order kinetics, if the concentration of the alkyl halide substrate is tripled and the concentration of the attacking nucleophile is simultaneously doubled, by what numerical factor will the rate of the reaction increase?
💡 Solution & Explanation
The rate law for a single-step $S_N2$ reaction is given by $\text{Rate} = k[\text{Substrate}][\text{Nucleophile}]$. If $[\text{Substrate}]$ becomes $3 \times [\text{Substrate}]$ and $[\text{Nucleophile}]$ becomes $2 \times [\text{Nucleophile}]$, the new rate calculation is $k(3[\text{Substrate}])(2[\text{Nucleophile}]) = 6 \times k[\text{Substrate}][\text{Nucleophile}]$. The overall rate increases by a factor of $6$.