Question

Give the formula of a reagent which will form a

precipitatewith a solution of MnCl2, but not with a solution of
NiCl2. In thesecond answer box, give the formula of the
precipitate.

Answer 1

The group reagent is H2S in the presence of NH4Cl .

Step-by-step explanation:

Mn is fourth group radical in qualitative analysis ;

the group reagent is H2S in the presence of NH4Cl .

then Mn precipitates as buff coloured sulphide , which is soluble in HCl .

MnS + 2HCl ---------> MnCl2 + H2S

on heating the solution with NaOH with bromine water, manganesedioxide gets precipitated.

MnCl2 + 2NaOH --------> Mn(OH)2 + 2NaCl

Mn(OH)2 + O -------> MnO2 + H2O

whereas NiS is insoluble in HCl. the nickel chloride gives a scarlet red precipitate with dimethy gly oxime.