The solubility product of $Mg(OH)_2$ is $9 \times 10^{-12}$. If the concentration of $Mg^{+2}$ is $0.01 \ M$,then the concentration of $OH^{-}$ is = .....

Consider two Group $IV$ metal ions $X^{2+}$ and $Y^{2+}$. $A$ solution containing $0.01 \ M$ $X^{2+}$ and $0.01 \ M$ $Y^{2+}$ is saturated with $H_2S$. The pH at which the metal sulphide $YS$ will form as a precipitate is . . . . . . (Nearest integer). (Given: $K_{sp}(XS)=1 \times 10^{-22}$ at $25^{\circ} C$, $K_{sp}(YS)=4 \times 10^{-16}$ at $25^{\circ} C$, $[H_2S]=0.1 \ M$ in solution, $K_{a1} \times K_{a2}(H_2S)=1.0 \times 10^{-21}$, $\log 2=0.30, \log 3=0.48, \log 5=0.70$)

When $H_2S$ gas is passed through a mixture containing $Mn^{2+}$,$Ni^{2+}$,$Cu^{2+}$,and $Hg^{2+}$ ions in an acidic aqueous solution,which of the following will precipitate?

The solubility product constant $K_{sp}$ of $Mg(OH)_2$ is $9.0 \times 10^{-12}.$ If a solution is $0.010 \ M$ with respect to $Mg^{2+}$ ion,what is the maximum hydroxide ion concentration which could be present without causing the precipitation of $Mg(OH)_2$?

Which of the following compounds does not dissolve in ammonium hydroxide solution?

The concentration of sulphide ion in $0.1 \ M \ HCl$ solution saturated with hydrogen sulphide is $1.0 \times 10^{-19} \ M$. If $10 \ mL$ of this is added to $5 \ mL$ of $0.04 \ M$ solution of the following: $FeSO_4, MnCl_2, ZnCl_2$ and $CdCl_2$,in which of these solutions will precipitation take place? Given $K_{sp}$ for $FeS = 6.3 \times 10^{-18}, MnS = 2.5 \times 10^{-13}, ZnS = 1.6 \times 10^{-24}, CdS = 8.0 \times 10^{-27}$.