The sulphide ion concentration `[S^(2-)]` in saturated `H_(2)S` solution is `1 xx 10^(-22)`. Which of the following sulphides should be quantitatively precipitated by `H_(2)S` in the presence of dil. HCl
`{:("Sulphide",,"Solubility Product"),("(I)",,1.4xx10^(-16)),("(II)",,1.2xx10^(-22)),("(III)",,8.2xx10^(-46)),("(IV)",,5.0xx10^(-34)):}`

Options

A. I, II
B. III, IV
C. II, III, IV
D. Only I

Answer

B

Explanation

Basic radicals of group II & IV are precipitated by `H_(2)S` in the form of their sulphides. Iind group in acidic medium & IV group in alkaline medium. They precipitate when ionic product increases than solubility product.