$(x)\begin{array}{*{20}{c}}
{O\,\,\,}\\
{||\,\,\,}\\
{C{H_3} - S - O - H}\\
{||\,\,\,\,}\\
{O\,\,\,\,}
\end{array}$
$\begin{array}{*{20}{c}}
{\,\,\,\,\,O}\\
{\,\,\,\,\,\,||}\\
{(y)\,\,\,C{H_3} - C - O - H}
\end{array}$
$(z)\,\, CH_3 -OH$
$\mathop {\begin{array}{*{20}{c}}
O \\
{||} \\
{Me - S - {O^\Theta }} \\
{||} \\
O
\end{array}}\limits_{3 - eq.\,R.S.} $ $>$ $\mathop {\begin{array}{*{20}{c}}
O \\
{||} \\
{Me - C - {O^\Theta }}
\end{array}}\limits_{2 - eq.\,R.S.} $ $>$ $Me - {O^\Theta }$
So Acidic strength order is $x>y>z$ so $\mathrm{pK}_{\mathrm{a}}$ is $z>y>x$


$(i)$ બેન્ઝિન $(ii)$ ટોલ્યુઇન
$(iii)$ ક્લોરોબેન્ઝિન $(iv)$ ફિનોલ