Question

Which of the following alkyl halides undergoes \(\text{SN}^1\) reaction most readily?

• A. \((\text{CH}_3)_3\text{C-F}\)
• B. \((\text{CH}_3)_3\text{C-Cl}\)
• C. \((\text{CH}_3)_3\text{C-Br}\)
• D. \((\text{CH}_3)_3\text{C-I}\)

Hint:

All four share the same tert-butyl carbocation; the best leaving group goes fastest.

Answer 1

The Correct Option is D

Step 1: Same cation:
Each substrate gives $(\text{CH}_3)_3\text{C}^+$, so carbocation stability is identical.

Step 2: What differs:
The strength of the C-X bond. C-I is longest and weakest, so it breaks most easily.

Step 3: Result:
The iodide reacts fastest in SN1, option (D).

Final Answer:
tert-Butyl iodide reacts fastest by SN1. \[ \boxed{\text{(D) }(\text{CH}_3)_3\text{C-I}} \]