What is the solubility of Mg(OH)2 (K_sp = 1.2x 10^-11) in a buffer of constant pH = 11.00?

JEE Main levelSingle correct optionDifficulty 2 of 3ia150

What is the solubility of $Mg (OH) X_{2}$ ( $K_{s p} = 1.2 \times 1 0^{- 11}$ ) in a buffer of constant pH $= 11.00$ ?

[OH X^{-}] = 1 0^{- 3} M

s = [Mg X^{2 +}] = K_{s p} / [OH X^{-}]^{2} = 1.2 \times 1 0^{- 11} /1 0^{- 6} = 1.2 \times 1 0^{- 5} M