Question

An aqueous solution of a substance gives a white precipitate on treatment with $dil.HCl$ which dissolves on heating. When $H_{2}S$ is passed through the hot acidic solution, a black precipitate is obtained. The substances are not :

• A. $H{g}_2^{2+}$ salt
• B. $C{u}^{2+}$ salt
• C. $A{g}^{+}$ salt
• D. $P{b}^{2+}$ salt

Answer 1

Answer: (A), (B), (D)

The correct options are
A $H{g}_2^{2+}$ salt
B $C{u}^{2+}$ salt
D $P{b}^{2+}$ salt

Option (C) is correct.

$A{g}^{+}$ gives a white precipitate on treatment with $dil.HCl$ which dissolves on heating. When $H_{2}S$ is passed through the hot acidic solution, a black precipitate is obtained.

For ex : $AgN{O}_3+HCl⟶AgCl\downarrow \left(whiteppt\right)+HN{O}_3$