Question

Which of the following alkyl halides will undergo \( S_N1 \) reaction most readily?

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

Hint:

In \( S_N1 \) reactions, the rate
determining step involves the departure of the leaving group. A good leaving group, such as \( \text{I}^
\), facilitates the reaction. The order of leaving group ability is \( I^
>Br^
>Cl^
>F^
\).

Answer 1

The Correct Option is D

In an \( S_N1 \) reaction, the leaving group must depart easily, and the carbocation formed must be stable. Among the halides, \( \text{I}^
\) is the best leaving group, followed by \( \text{Br}^
\), \( \text{Cl}^
\), and \( \text{F}^
\). Since \( \text{I}^
\) is the best leaving group, the alkyl halide with \( \text{I} \) will undergo \( S_N1 \) reactions most readily. Final Answer: The alkyl halide \( (\text{CH}_3)_3 \text{C} \, \text{I} \) will undergo the \( S_N1 \) reaction most readily.