In the precipitation of the iron group $(III)$ in qualitative analysis,ammonium chloride is added before adding ammonium hydroxide to :

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: $\lambda^{\circ}_{(Ag^{+})} = 6 \times 10^{-3} \ S \ m^2 \ mol^{-1}$,$\lambda^{\circ}_{(Br^{-})} = 8 \times 10^{-3} \ S \ m^2 \ mol^{-1}$,$\lambda^{\circ}_{(NO_3^-)} = 7 \times 10^{-3} \ S \ m^2 \ mol^{-1}$.

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

In the precipitation of the group $III$ in qualitative analysis,ammonium chloride is added before adding ammonium hydroxide to:

If acetic acid is mixed with sodium acetate,then the ${H^{+}}$ ion concentration will be:

Define the common ion effect and explain it with an example.