Question

$2AgCl(s) + CO_{3}^{2 -} \rightleftharpoons Ag_{2}CO_{3}(s) + 2Cl^{-}$

2 M 0

Equ. $(2 - x)M$ $2x = \frac{0.00355}{25.5}$

$\approx 2M\therefore x = 5 \times 10^{- 5}$

Now, $K_{eq} = \frac{\left\lbrack Cl^{-} \right\rbrack^{2}}{\left\lbrack CO_{3}^{2 -} \right\rbrack} \times \frac{\left\lbrack Ag^{+} \right\rbrack^{2}}{\left\lbrack Ag^{+} \right\rbrack^{2}} = \frac{K_{sp}^{2}(AgCl)}{K_{sp}\left( Ag_{2}CO_{3} \right)}$

Or, $\frac{\left( 5 \times 10^{- 5} \right)^{2}}{2} = \frac{K_{sp}^{2}(AgCl)}{8 \times 10^{- 12}}$

$\Rightarrow K_{sp}(AgCl) = 1 \times 10^{- 10}$