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Chemistry · EQUILIBRIUM
हिन्दीWhen \( \text{HCl} \) gas is passed through a saturated solution of \( \text{NaCl} \), pure \( \text{NaCl} \) precipitates out while impurities like \( \text{MgSO}_4 \) and \( \text{Na}_2\text{SO}_4 \) remain dissolved. The underlying reason for this phenomenon is:
Correct answer · Option 4
Common ion effect increasing \( [\text{Cl}^-] \), causing the ionic product of \( \text{NaCl} \) to exceed its \( K_{sp} \)
Explanation
Passing \( \text{HCl} \) introduces high \( [\text{Cl}^-] \) via complete ionization, which shifts \( \text{NaCl}(s) \rightleftharpoons \text{Na}^+ + \text{Cl}^- \) to the left because \( Q_{sp} > K_{sp} \), selectively precipitating pure \( \text{NaCl} \).
