Solution:
When HCl gas is passed through a saturated
solution of NaCl, the concentration of chloride ions (Cl-) increases due to the
dissociation of HCl. This increase in the concentration of Cl- ions results in
the formation of solid NaCl due to a decrease in the solubility of NaCl. This
is because of the common ion effect, where the presence of a common ion in a
solution reduces the solubility of a slightly soluble salt. As a result, the
NaCl is recovered in crystalline form.