The presence of $NH_4Cl$ in the test solution while precipitating group $III-A$ hydroxides (in qualitative inorganic analysis) helps in:

The following equilibrium exists in aqueous solution: $CH_3COOH \rightleftharpoons CH_3COO^{-} + H^{+}$. If dilute $HCl$ is added without a change in temperature,then the:

Given below are two statements:
Statement $I$: On passing $HCl_{(g)}$ through a saturated solution of $BaCl_2$,at room temperature white turbidity appears.
Statement $II$: When $HCl$ gas is passed through a saturated solution of $NaCl$,sodium chloride is precipitated due to common ion effect.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which is not an example of common ion effect?

Test tubes $A$ and $B$ contain solutions of $NH_4Cl$ and $NaCl$ respectively. What happens if $Mg(OH)_2$ solution is added to both test tubes?

Statement $A$: Addition of $NH_4OH$ in the presence of excess $NH_4Cl$ to an aqueous solution of $BaCl_2$ results in the precipitation of $Ba(OH)_2$.
Reason $R$: $Ba(OH)_2$ is insoluble in water.