The solubility product of salt $B_2A$ is $3.2 \times 10^{-11}$ at $298 \ K$. What is the solubility of the salt at the same temperature?

An aqueous solution contains $SCN^{-}$,$Br^{-}$,$I^{-}$,and $Cl^{-}$ ions. When $AgNO_3$ is added to the solution,which of these will precipitate first? Given: $K_{sp}(AgCl) = 1.2 \times 10^{-10}$,$K_{sp}(AgI) = 1.7 \times 10^{-16}$,$K_{sp}(AgSCN) = 7.1 \times 10^{-7}$,$K_{sp}(AgBr) = 3.5 \times 10^{-13}$.

Assign $A, B, C, D$ from the given type of reaction.
$CaC_2O_4 \downarrow + CH_3COOH \longrightarrow$ No reaction

The moles of $Ag^{+}$ which must be added to decrease the concentration of $Cl^{-}$ from $4 \times 10^{-5} \ M$ to $10^{-5} \ M$ in $100 \ mL$ solution,if $K_{sp}$ for $AgCl$ is $10^{-10} \ M^2$ at $25 \ ^oC$.

The $K_{sp}$ expression for $Ca_3(PO_4)_2$ is:

What is the maximum concentration of equimolar solutions of ferrous sulphate and sodium sulphide so that when mixed in equal volumes,there is no precipitation of iron sulphide? (For iron sulphide,$K_{sp} = 6.3 \times 10^{-18}$).