Identify the correct order of solubility of `Na_(2)S,CuS` and ZnS in aqueous solution

Options

A. CuSgtZnSgt`Na_(2)S`
B. `ZnS gt Na_(2)S gt CuS`
C. `Na_(2)S gt CuS gt ZnS`
D. `Na_(2)S gt ZnS gt CuS`

Answer

D

Explanation

Sodium salts are highly soluble. `Cu^(2+)` belongs to the `II^(nd)` group in salt analysis and is precipitated as `CuS`, whereas `Zn^(2+)` belongs to the IV group and is precipitated as ZnS
after CuS because of higher `K_(SP)` of `ZnS`.