Question

The rate of reaction of t-butyl bromide and NaOH in water depends on the concentration of:

• A. Both t-butyl bromide & NaOH
• B. NaOH
• C. Independent of concentration
• D. t-butyl bromide

Hint:

For SN1 reactions, rate = k[alkyl halide]; for SN2, rate = k[alkyl halide][nucleophile].

Answer 1

The Correct Option is D

Step 1: Identify the substrate and expected mechanism.
tert-Butyl bromide is a tertiary alkyl halide. Its three bulky methyl groups block backside attack, ruling out S\(_N\)2. It reacts via S\(_N\)1 (ionisation first).

Step 2: Write the rate law.
S\(_N\)1 is unimolecular -- the slow step involves only the alkyl halide. Rate \(= k[t\text{-BuBr}]\). The concentration of NaOH does not appear.
\[ \boxed{\text{Rate} = k[t\text{-BuBr}]} \]