An aqueous solution of a substance gives a white precipitate on treatment with dilute hydrochloric acid, which dissolves on heating. When hydrogen sulphide is passed through the hot acidic solution, a black precipitate is obtained. The substance is a :

The correct option is D ${Pb}^{2+}$salt
The given substance is a salt of lead(II). It reacts with dil HCl to form white precipitate of lead chloride.
$P{b}^{2+}+2HCl\to PbC{l}_2\downarrow \left(black\right)+2H^{+}$
Lead chloride has low solubility in cold water and it dissolves in hot water.
It reacts with sulphide ions from hydrogen sulphide to form a balck precipitate of lead sulphide.
$PbC{l}_2+H_{2}S\to PbS\downarrow \left(black\right)+2HCl$