Question

Which order of kinetics is followed by the reaction between tert-butyl bromide and hydroxide ion to give tert-Butyl alcohol?

• A. Zero-order kinetics.
• B. First-order kinetics.
• C. Second-order kinetics.
• D. Third-order kinetics.

Hint:

A tertiary halide reacts by the SN1 path, so only the halide appears in the rate law.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
A tertiary alkyl halide reacts with hydroxide mainly by the \(S_{N}1\) mechanism.
The order is decided by the slow step.

Step 2: Mechanism
Slow step: \((\text{CH}_{3})_{3}\text{C-Br}\rightarrow (\text{CH}_{3})_{3}\text{C}^{+}+\text{Br}^{-}\).
The stable tertiary carbocation then combines quickly with \(\text{OH}^{-}\).

Step 3: Rate law
Only the halide is involved in the slow step, so \(\text{Rate}=k[(\text{CH}_{3})_{3}\text{CBr}]\), independent of \([\text{OH}^{-}]\).
The reaction is first order.

Final Answer:
The reaction follows first-order kinetics, option (B). \[ \boxed{\text{(B) }\text{First-order kinetics.}} \]