Question

In an acidified aqueous solution of $Mn ^{2+}, Ni ^{2+}, Cu ^{2+}$ and $Hg ^{2+}$ ions, $H _{2} S$ gas was passed. Precipitates are

• A. MnS and CuS
• B. NiS and HgS
• C. MnS and NiS
• D. CuS and HgS

Answer 1

Answer: (D)

CuS and HgS

Answer 2

The black precipitate of $CuS$ and $HgS$ will be formed.
$Cu ^{2+}+ H _{2} S \rightarrow CuS (\text { black }) \downarrow+ H _{2} \uparrow$
$Hg ^{2+}+ H _{2} S \rightarrow HgS (\text { black }) \downarrow+ H _{2} \uparrow$