Browse Questions

# Identify the correct order of solubility of $Na_2S, CuS$ and $ZnS$ in aqueous solution

(a) $CuS > ZnS > Na_2S$
(b) $ZnS > Na_2S > CuS$
(c) $Na_2S > CuS > ZnS$
(d) $Na_2S > ZnS > CuS$

Toolbox:
• More the $K_{sp}$, for similar compounds more is the solubility.
Answer: $Na_2S > ZnS > CuS$

$Na_2S$ is freely soluble in water. $K_{sp}$ of group II (CuS) is less than the $K_{sp}$ of Group IV (ZnS) ions.
Thus, correct order is $Na_2S > ZnS > CuS$.