245g impure sample of $KCl{O}_3\left(s\right)$  on heating gives $12g{O}_2\left(g\right)$  according to $2KC1O_3\left(s\right)\to 2KC1\left(s\right)+3O_2\left(g\right)$ calculate % purity of sample?

$2KCl{O}_3\to 2KCl+3O_2$

Let the %  purity=x
Mole of  $KCl{O}_3=\frac{245}{122.5}\times \frac{x}{100}=\frac{2x}{10\left(\right)}$
Mole of  $O_2=\frac{2x}{100}\times \frac{3}{2}$   $\frac{2x}{100}\times \frac{3}{2}\times 32=12$

(% purity of sample)  $x=12.5$