2 moles of a mixture of  ${\text{O}}_{\text{2}}$ and  ${\text{O}}_{\text{3}}$ is reacted with excess of acidified solution of KI. The iodine liberated required 1L of 2M hypo solution for complete reaction. The weight % of  ${\text{O}}_{\text{3}}$  in the initial sample is x. Find x.

 $\begin{array}{cc}\text{KI}& \begin{array}{cc}+& \begin{array}{cc}{\text{O}}_{\text{3}}& \begin{array}{cc}\to & {\text{I}}_2+{\text{H}}_{\text{2}}\text{O}+O_2.\end{array}\end{array}\end{array}\end{array}$
$\begin{array}{cc} & \begin{array}{cc} & \begin{array}{cc}\text{v.f\hspace{0.17em}=\hspace{0.17em}2}& \begin{array}{cc} & \text{v.f}=2\end{array}\end{array}\end{array}\end{array}$
$\begin{array}{cc} & \begin{array}{cc} & \begin{array}{cc}\text{moles}& \begin{array}{cc} & \end{array}\end{array}\end{array}\end{array}$
$\begin{array}{cc}{\text{I}}_2& \begin{array}{cc}+& \begin{array}{cc}{\text{Na}}_{\text{2}}{\text{S}}_{\text{2}}{\text{O}}_{\text{2}}& \begin{array}{cc}\to {\text{Na}}_{\text{2}}{\text{S}}_{\text{4}}{\text{O}}_{\text{6}}& \end{array}\end{array}\end{array}\end{array}$
$\begin{array}{cc}\text{v.f}=2& \begin{array}{cc}\text{m}=2& \begin{array}{cc} & \begin{array}{cc} & \end{array}\end{array}\end{array}\end{array}$
$\begin{array}{cc}& \begin{array}{cc}\text{V}=1\text{L}& \begin{array}{cc} & \begin{array}{cc} & \end{array}\end{array}\end{array}\end{array}$
$\begin{array}{cc}& \begin{array}{cc}\text{v.f}=1& \begin{array}{cc} & \begin{array}{cc} & \end{array}\end{array}\end{array}\end{array}$
Eq of  ${\text{O}}_{\text{3}}={\text{eq\hspace{0.17em}of\hspace{0.17em}I}}_{\text{2}}=\text{eq\hspace{0.17em}\hspace{0.17em}of\hspace{0.17em}\hspace{0.17em}hypo}$
$\Rightarrow 2\times x=2$
        $x=1\text{\hspace{0.17em}mole}$
$\Rightarrow weight\%of{O}_3=\frac{1\times 48}{1\times 48+1\times 32}\times 100$
         $=\frac{3}{5}\times 100=60\%$