Question

Which of the following gives the fastest $S_{N}1$ reaction?

• A. $C{H}_{3}Cl$
• B. $C{H}_{3}C{H}_{2}Cl$
• C. $C{H}_{3}CH\left(C{H}_3\right)Cl$
• D. $C(C{H}_3{)}_{3}Cl$

Answer 1

The correct option is D $C(C{H}_3{)}_{3}Cl$

A methyl carbocation will be formed in option (a), an ethyl carbocation will be formed in option (b) and a secondary carbocation will be formed in option (c). In option (d), a tertiary carbocation will be formed, which is the most stable due to more $+H$ and $+I$ effects. Therefore, it gives the fastest $S_{N}1$ reaction.

Hence, option (d) is the correct answer.