On addition of conc `HNO_(3)` to the aqueous solution of common
salt, sodium chloride crystallises out. Give reason.

Explanation

Aqueous sodium chloride solution cotains
`NaCI(s) _ H_(2)O rarr underset(ion)underset("Hyrated sodium")([Na(H_(2)O)_(x)])^(o+) + underset(ion)underset("Hydrated chloride")([CI(H_(2)O)_(y)]^(Θ)`
On addition of conc `HNO_(3)` the reaction between hydrated ions and conc `HNO_(3)` takes place, thereby water molecules which were previously forming hydrated species are removed. The ions are thus unsolvated and thus unsolvated and hence reform the crystal lattice resulting in the crystallisation of sodium chloride (NaCI).