Question

In an acidified aqueous solution of $M{n}^{2+},N{i}^{2+},C{u}^{2+}$ and $H{g}^{2+}$ 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

In cationic estimation group, Cu${}^{2+}$ and Hg ${}^{2+}$ are present in group II while Mn${}^{2+}$ and Ni${}^{2+}$ are present in group IV.

The group reagent of groups II is H${}_2$S gas in presence of HCl (dil) while of group IV it is H${}_2$S gas in presence of NH${}_4$OH. So, H${}_2$S gas when passed in acidified solutions of given cations only Cu${}^{2+}$ and Hg${}^{2+}$ will get precipitated as CuS and HgS.