Why is pure $NaCl$ precipitated when $HCl$ gas is passed through a saturated solution of $NaCl$?

When $H_2S$ gas is passed into a certain solution,it reacts to form a white precipitate. The solution referred to contains ions of

At $298 \ K$ the molar solubility of $Cd(OH)_2$ in $0.1 \ M \ KOH$ solution is $x \times 10^{-y}$. The values of $x$ and $y$ are respectively (at $298 \ K, \ K_{sp}$ of $Cd(OH)_2 = 2.5 \times 10^{-14}$)

In which of the following,the solubility of $AgCl$ will be minimum?

$A$ saturated solution of $BaSO_4$ at $25^\circ C$ is $4 \times 10^{-5} \ M$. The solubility of $BaSO_4$ in $0.1 \ M \ Na_2SO_4$ at this temperature will be:

We have taken a saturated solution of $AgBr$. The $K_{sp}$ of $AgBr$ is $12 \times 10^{-14}$. If $10^{-7} \ mol$ of $AgNO_3$ are added to $1 \ L$ of this solution,find the conductivity (specific conductance) of this solution in terms of $10^{-7} \ S \ m^{-1}$ units.
Given: $\lambda^{\circ}_{(Ag^{+})} = 6 \times 10^{-3} \ S \ m^2 \ mol^{-1}$,$\lambda^{\circ}_{(Br^{-})} = 8 \times 10^{-3} \ S \ m^2 \ mol^{-1}$,$\lambda^{\circ}_{(NO_3^-)} = 7 \times 10^{-3} \ S \ m^2 \ mol^{-1}$.