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:

Which pair will show the common ion effect?

On passing $HCl$ gas in a saturated solution of $NaCl$,the solubility of $NaCl$

When $H_2S$ gas is passed through a solution containing $HCl$,it precipitates the cations of the second group of qualitative analysis but not those belonging to the fourth group. This is because:

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:

Addition of conc. $HCl$ to saturated $BaCl_2$ solution precipitates $BaCl_2$; because