Which pair will show the common ion effect?

When $0.05 \ M$ dimethylamine is dissolved in $0.1 \ M$ $NaOH$ solution,the percentage dissociation of dimethylamine is: $(K_b)_{(CH_3)_2NH} = 5 \times 10^{-4}$

Consider the following equilibrium: $AgCl_{(s)} + 2NH_{3(aq)} \rightleftharpoons [Ag(NH_3)_2]^+_{(aq)} + Cl^-_{(aq)}$. $A$ white precipitate of $AgCl$ appears on adding which of the following?

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

If the maximum concentration of $PbCl_2$ in water at $298 \, K$ is $0.01 \, M$,what is its maximum concentration in $0.1 \, M \, NaCl$ solution?

The solubility of $AgI$ in $NaI$ solution is less than that in pure water because