Which of the following substances is insoluble in dilute hydrochloric acid?

If the ${K_{sp}}$ for $HgSO_4$ is $6.4 \times 10^{-5}$,then the solubility of the salt is:

On adding $0.1 \ M$ solution each of $[Ag^+]$,$[Ba^{2+}]$,and $[Ca^{2+}]$ to a $Na_2SO_4$ solution,which species precipitates first? Given: $K_{sp}(BaSO_4) = 10^{-11}$,$K_{sp}(CaSO_4) = 10^{-6}$,$K_{sp}(Ag_2SO_4) = 10^{-5}$.

Increasing order of solubility of $AgCl$ in $(i) H_2O$, $(ii) 1 \ M \ NaCl \ (aq.)$, $(iii) 1 \ M \ CaCl_2 \ (aq.)$ and $(iv) 1 \ M \ NaNO_3 \ (aq.)$ solution.

Zirconium phosphate $[Zr_3(PO_4)_4]$ dissociates into three zirconium cations of charge $+4$ and four phosphate anions of charge $-3$. If molar solubility of zirconium phosphate is denoted by $S$ and its solubility product by $K_{sp}$,then which of the following relationships between $S$ and $K_{sp}$ is correct?

Calculate the molar solubility of $Ni(OH)_2$ in $0.10 \ M \ NaOH$. The solubility product of $Ni(OH)_2$ is $2 \times 10^{-15}$.