$\begin{array}{*{20}{c}} {{\text{Tert}}{\text{. Butyl Carbocation}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\text{Sec}}{\text{. Butyl carbocation}}} \\ { \downarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\end{array}$
More stable due to Hyperconjugation effect.
$(i)\,\,RC \equiv \mathop C\limits^ \ominus $
$(ii)\,\,[IMAGE]$
$(iii)\,\,{R_2}C = \mathop C\limits^ \ominus H$
$(iv)\,\,{R_3}C - \mathop C\limits^ \ominus {H_2}$
$\begin{matrix}
\overset{\Theta }{\mathop{\overset{\centerdot \,\centerdot }{\mathop{C}}\,}}\,{{H}_{2}}-C-C{{H}_{3}} \\
|| \\
O \\
\end{matrix}$ અને $\begin{matrix}
C{{H}_{2}}=C-C{{H}_{3}} \\
| \\
:\underset{\Theta }{\mathop{\underset{\centerdot \,\centerdot }{\mathop{O}}\,}}\,: \\
\end{matrix}$