# Which of the following carbocation is most stable?

Question:

Which of the following carbocation is most stable?

(a) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{C} . \stackrel{+}{\mathrm{C}} \mathrm{H}_{2}$

(b) $\left(\mathrm{CH}_{3}\right)_{3} \stackrel{+}{\mathrm{C}}$

(c) $\mathrm{CH}_{3} \mathrm{CH}_{2} \stackrel{+}{\mathrm{C}} \mathrm{H}_{2}$

(d) $\mathrm{CH}_{3} \stackrel{+}{\mathrm{C}} \mathrm{H} \mathrm{CH}_{2} \mathrm{CH}_{3}$

Solution:

$\left(\mathrm{CH}_{3}\right)_{3}{ }_{\mathrm{C}}^{+}$is a tertiary carbocation. A tertiary carbocation is the most stable carbocation due to the electron releasing effect of three methyl groups. An increased $+$ I effect by three methyl groups stabilizes the positive charge on the carbocation.