Question

Which of the following will give a black precipitate with $H_{2}S$ in acidic medium ?
(A) ${Cu}^{2+}$ (B) $C{o}^{2+}$ (C) $H{g}^{2+}$ (D) $N{i}^{2+}$

• A. A
• B. B
• C. C
• D. D

Answer 1

Answer: (A), (C)

The correct options are
A A
C C

${Cu}^{+2}+H_{2}S\to CuS+2H^{+}$

The CuS formed is a black precipitate

${Hg}^{+2}+H_{2}S\to HgS+2H^{+}$

The HgS formed is a black precipitate

So Option a,c are correct