1) Passing $H_{2}S$ gas into a mixture of $Mn^{2+},Ni^{2+},Cu^{2+}$ and $Hg^{2+}$ ions in an acidified aqueous solution precipitates A) CuS and HgS B) MnS and CuS C) MnS and NiS D) NiS and HgS Answer: Option AExplanation:In an acidic medium,$H_{2}S$ is very feebly ionized giving very small concentration of sulphide ion for precipitation. Therefore, the most insoluble salts Cus and HgS are precipitated only.
