An aqueous solution of a substance, on treatment with dilute HCl, gives a white precipitate soluble in hot water. When `H_(2)S` is passed through the hot acidic solution, a black precipitate is formed. The substance is:

Options

A. `Hg_(2)^(+2)`
B. `Hg^(2+)`
C. `Zn^(2+)`
D. `Cd^(2+)`

Answer

A

Explanation

`Hg_(2)^(2+) + 2HCl to underset("white")(Hg_(2)Cl_(2) darr) + 2H^(+)`