${\left[ F ^{-}\right]=\frac{25 \times 0.02}{50}=0.01 M }$
${\left[ Ba ^{+2}\right]\left[ F ^{-}\right]^2=25 \times 10^{-7}}$
$K _{ sp }=5 \times 10^{-7} \text { (given) }$
$\text { Ratio }=\frac{\left[ Ba ^{+2}\right]\left[ F ^{-}\right]^2}{ K _{ sp }}=5$
${H_2}{O_2}\, + \,{H_2}O\, \rightleftharpoons \,{H_3}{O^ + }\, + \,HO_2^ - $