$1. {{H}_{3}}C-\overset{+}{\mathop{O}}\,{{H}_{2}}\to CH_{3}^{+}+{{H}_{2}}O$
$2. (CH_3)_3 C - \overset{+}{\mathop{O}}\,{{H}_{2}} \to (CH_3)_3 C^+ + H_2O$
$3. (CH_3 )_2CH - \overset{+}{\mathop{O}}\,{{H}_{2}} \to (CH_3)_2 CH^+ + H_2O$
${\left( {C{H_3}} \right)_2}CH - OH\xrightarrow{{PB{r_3}}}X\xrightarrow{{alko.\,\,KOH}}Y\xrightarrow[{(ii)\,{H_3}{O^ + }}]{{(i)\,{H_2}S{O_4}}}Z$