During preparation of table salt , HCl gas is passed through sea water after evaporation to a particular concentration . Explain the phenomenon .

Explanation

`N_(2)` gas is neither a reactant nor a product of the given reaction. `SO_(2)` in the given reaction system, it behaves as an inert gas. Keeping temperature and volume constant, if `N_2` gas added to the reaction system at equilibrium , the total pressure of `PCl_5(g) PCl_(3) "and" Cl_(2)(g)` remain unaffected. As a result , there is no effect on the equilibrium position on the reaction due to addition of `N_(2)` gas under the conditoins of constant temperature and volume.
If `N_2` gas is added to the given reaction system at equilibrium,keeping temperature and pressure constant, the volume of the reaction system increases. This causes the partial pressure of `PCl_(5)(g), PCl_(3)(g) "and" Cl_(2)(g)` to get reduced. According to Le Chatelier's principle, in a situation of this, the equilibrium position of the reaction shifts in the direction that is associated with the increase in volume (or the number of moles of gas.) For the given reaction `Delta n gt 0`. So the equilibrium position will shift to the right.