At equilibrium, if to a saturated solution of $NaCl,\,HCl$ is passed, $NaCl$ gets precipitated because

A very dilute acidic solution of $Cd^{2+}$ and $Ni^{2+}$ gives only yellow ppt. of  $CdS$ on passing $H_2S$, this is due to

The molar solubility of $\mathrm{Zn}(\mathrm{OH})_{2}$ in $0.1 \,\mathrm{M} \,\mathrm{NaOH}$ solution is $\mathrm{x} \times 10^{-18} \,\mathrm{M}$. The value of $\mathrm{x}$ is …… . (Nearest integer)

(Given : The solubility product of $\mathrm{Zn}(\mathrm{OH})_{2}$ is $\left.2 \times 10^{-20}\right)$

A mixture of $100\, m\, mol$ of $Ca(OH)_2$ and $2\, g$ of sodium sulphate was dissolved in water and the volume was made upto $100\, mL$. The mass of calcium sulphate formed and the concentration of $OH^-$ in resulting solution, respectively are 

(Molar mass of $Ca(OH)_2, Na_2SO_4$ and $CaSO_4$ are $74, 143$ and $136\, g\, mol^{-1}$ respectively; $K_{sp}$ of $Ca(OH)_2$ is $5.5 \times 10^{-6}$)

In qualitative analysis, the metals of group $I$ can be separated from other ions by precipitating them as chloride salts. A solution initially contains $Ag^+$ and $Pb^{2+}$ at a concentration of $0.10 \,M.$  Aqueous $HCl$ is added to this solution until the $Cl^-$ concentration is $0.10\, M.$What will the concentrations of $Ag^+$ and $Pb^{2+}$ be at equilibrium ? ($K_{sp}$ for $AgCl = 1.8 \times 10^{-10},$$ K_{sp}$ for $PbCl_2 = 1.7 \times 10^{-5}$)