Upon treatment with ammoniacal H 2 S , the metal ion that precipitates as a sulphide is
Solution
Among Fe3+, Al3+, Mg2+ and Zn2+, only Zn2+ is precipitated with ammoniacal H2S as ZnS.
The group III metal ions, in presence of NH4OH when H2S is bubbled through filtrate Ni2+, Co2+ and Zn2+ are precipitated as sulphides.
Asked in: JEE Advanced 2013 (Paper 1)