Sodium chloride is purified by passing hydrogen chloride gas in an impure solution of sodium chloride. It is based on

Pure $NaCl$ is prepared by passing $HCl$ gas through a saturated solution of common salt in water. The principle used is:

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

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

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:

Solubility of $AgCl$ in conc. $HCl$ is ...... than in water.