Indentify the correct order of solubility in aqueous medium

Options

A. `CuS gt ZnS gt Na_2S`
B. `ZnS gt Na_2S gt CuS`
C. `Na_2S gt CuS gt ZnS`
D. `Na_2S gt ZnS gt CuS`

Answer

D

Explanation

Ionic compounds are more soluble in water or in aqueous medium.
According to Fajan's rule.
Size of the cation increases the ionic character also increases. Ionic character `prop` size of cation (if anion is same ) The order of size of cations is
`Na^(+) gt Zn^(2+) gt Cu^(2+)`
`therefore` The order of ionic character and hence, of solubility in water is as
`Na_2S gt ZnS gt CuS`