JEE Main 2024 — Chemical Equilibrium Question with Solution

To determine the correctness of the statements, we'll analyze each one individually by applying principles of solubility, common ion effect, and chemical equilibria.

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Statement I:

On passing ${\mathrm{HCl}}_{(g)}$ through a saturated solution of ${\mathrm{BaCl}}_2$ at room temperature, white turbidity appears.

Analysis:

Dissolution of HCl Gas:

When ${\mathrm{HCl}}_{(g)}$ is bubbled through water, it dissolves and dissociates completely:

${\mathrm{HCl}}_{(aq)}\to {\mathrm{H}}_{(aq)}^{+}+{\mathrm{Cl}}_{(aq)}^{-}$

This increases the concentration of ${\mathrm{Cl}}^{-}$ ions in the solution.

Effect on BaCl₂ Solubility:

The solubility equilibrium of ${\mathrm{BaCl}}_2$ in water is:

${\mathrm{BaCl}}_2\leftrightarrow {\mathrm{Ba}}_{(aq)}^{2+}+2{\mathrm{Cl}}_{(aq)}^{-}$

Adding more ${\mathrm{Cl}}^{-}$ shifts the equilibrium to the left (Le Chatelier's Principle), causing ${\mathrm{BaCl}}_2$ to precipitate.

The precipitation of ${\mathrm{BaCl}}_2$ manifests as a white turbidity.

Conclusion:

Statement I is correct.

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Statement II:

When $\mathrm{HCl}$ gas is passed through a saturated solution of $\mathrm{NaCl}$, sodium chloride is precipitated due to common ion effect.

Analysis:

Dissolution of HCl Gas:

Similar to before, $\mathrm{HCl}$ increases ${\mathrm{Cl}}^{-}$ ion concentration.

Effect on NaCl Solubility:

The solubility equilibrium of $\mathrm{NaCl}$ is:

$\mathrm{NaCl}\leftrightarrow {\mathrm{Na}}_{(aq)}^{+}+{\mathrm{Cl}}_{(aq)}^{-}$

However, $\mathrm{NaCl}$ is highly soluble in water, and its solubility is not significantly affected by the common ion effect from ${\mathrm{Cl}}^{-}$.

The solubility product ($K_{sp}$) of $\mathrm{NaCl}$ is large, and the addition of ${\mathrm{Cl}}^{-}$ ions does not cause $\mathrm{NaCl}$ to precipitate under normal conditions.

No precipitation occurs; the solution remains clear.

Conclusion:

Statement II is incorrect.

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Final Answer:

Statement I is correct but Statement II is incorrect.