$1. {{H}_{3}}C-\overset{+}{\mathop{O}}\,{{H}_{2}}\to CH_{3}^{+}+{{H}_{2}}O$
$2. (CH_3)_3 C - \overset{+}{\mathop{O}}\,{{H}_{2}} \to (CH_3)_3 C^+ + H_2O$
$3. (CH_3 )_2CH - \overset{+}{\mathop{O}}\,{{H}_{2}} \to (CH_3)_2 CH^+ + H_2O$



$\begin{array}{*{20}{c}}
{{C_2}{H_5}MgBr + {H_2}C - C{H_2}\xrightarrow{{{H_2}O}}} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\backslash \,\,\,\,/} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O}
\end{array}A$
