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

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

$H_2S$ will precipitate the sulphides of all the metals from the solution of chlorides of $Cu, Zn$ and $Cd,$ if

The following equilibrium exists in an aqueous solution of hydrogen sulphide: $H_2S \rightleftharpoons H^{+} + HS^{-}$. If dilute $HCl$ is added to an aqueous solution of $H_2S$ without any change in temperature,what happens?

Which is not an example of common ion effect?

Which pair will show the common ion effect?