$\mathop {C{H_3} - \mathop C\limits^ \oplus H - C{H_3}}\limits_I $
$\mathop {C{H_3} - \mathop C\limits^ \oplus H - OC{H_3}}\limits_{II} $
$\mathop {C{H_3} - \mathop C\limits^ \oplus H - C{H_2} - OC{H_3}}\limits_{III} $
\(\mathop {\mathop {C{H_3} \to \mathop C\limits^ \oplus H \leftarrow C{H_3}}\limits_I }\limits_{ + I - effect\,of\,two\,methyl\,group\,stabilise\,the\,carbocation\,(I)} \) ;
\(\mathop {\mathop {C{H_3} \to \mathop C\limits^ \oplus H - \mathop O\limits_{\,}^{\,} - C{H_3}}\limits_I }\limits_{Strong\, + R - effect\,of\, - OC{H_3}\,group\,stabilise\,the\,carbocation\,(II)} \)
\(\mathop {\mathop {C{H_3} - \mathop C\limits^ \oplus H - C{H_2} \to OC{H_3}}\limits_{III} }\limits_{ - I - effect\,of\, - OC{H_{3\,}}group\,stabilise\,the\,carbocation\,(III)} \)
Thus, the stability of carbocation decreases in the order,
\(I I>I>I I I\)
$(x)\begin{array}{*{20}{c}}
{O\,\,\,}\\
{||\,\,\,}\\
{C{H_3} - S - O - H}\\
{||\,\,\,\,}\\
{O\,\,\,\,}
\end{array}$
$\begin{array}{*{20}{c}}
{\,\,\,\,\,O}\\
{\,\,\,\,\,\,||}\\
{(y)\,\,\,C{H_3} - C - O - H}
\end{array}$
$(z)\,\, CH_3 -OH$
$\mathop {{H_3}C\mathop C\limits^ \ominus {H_2}}\limits_{(i)} \,,$$\mathop {{H_2}C = \mathop C\limits^ \ominus H}\limits_{(ii)} $ અને $\mathop {H - C \equiv \mathop C\limits^ \ominus }\limits_{(iii)} $
$(I)$ $C{H_2} = CH\mathop C\limits^ + HC{H_3}$
$\begin{array}{*{20}{c}}
{{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{H_3}} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,} \\
{(II)\,\,\,\,\,\,\,\,\,\,C{H_2} = C - \mathop {{\text{ }}C}\limits^ + {H_2}}
\end{array}$
$(III)$ $C{H_3}CH = CH\mathop C\limits^ + {H_2}$
$[Nu^-=(A) \,PhO^-, (B)\,AcO^-, (C)\, HO^-, (D)\, CH_3O^-]$