An aqueous solution of a substance gives a white precipitate on treatment with dil. HCl which dissolves on…
An aqueous solution of a substance gives a white precipitate on treatment with dil. HCl which dissolves on heating. When $\mathrm{H}_{2} \mathrm{~S}$ is passed through the hot acidic solution, a black precipitate is obtained. The substance is a
$\mathrm{Hg}_{2}^{2+}$ salt
$\mathrm{Cu}^{2+}$ salt
$\mathrm{Ag}^{+}$ salt
$\mathrm{Pb}^{2+}$ salt
Solution
$\mathrm{PbCl}_{2}$ is insoluble in cold water, soluble in hot water and PbS is black ppt in acidic medium.