• question_answer Why pure $NaCl$ is precipitated when $HCl$ gas is passed in a saturated solution of $NaCl$ [NCERT 1977; MP PMT 1987; CPMT 1974, 78, 81] A)                 Impurities dissolves in $HCl$ B)                 The value of $[N{{a}^{+}}]$and $[C{{l}^{-}}]$ becomes smaller than ${{K}_{sp}}$ of $NaCl$ C)                 The value of $[N{{a}^{+}}]$and $[C{{l}^{-}}]$ becomes greater than ${{K}_{sp}}$ of $NaCl$ D)                 $HCl$dissolves in the water

$NaC{{l}_{(s)}}$ ⇌ $N{{a}^{+}}_{(\text{aq})}+C{{l}^{-}}_{(\text{aq})}$                     $HCl$  ⇌ ${{H}^{+}}+C{{l}^{-}}$                                 The increase in $[C{{l}^{-}}]$ brings in an increase in $[N{{a}^{+}}]\,\,$$[C{{l}^{-}}]$which will lead for backward reaction because ${{K}_{sp}}\,NaCl=[N{{a}^{+}}]\,\,[C{{l}^{-}}]$.