Question

Why is mercuric chloride added during estimation of iron?

Answer 1

Hey Dear,

◆ Answer -

Mercuric chloride added during estimation of iron so as to remove extra Sn2+.

◆ Explaination -

During estimation of the iron from given solution, ferric ion is reduced to ferrous ion by stannous chloride in acidic medium.

2Fe3+ + Sn2+ --> 2Fe2+ + Sn4+

Excess Sn2+ prepared here is removed by adding mercuric chloride which gets converted to insoluble mercurous chloride.

Sn2+ + 2HgCl2 + Hg2Cl2 + Sn4+ + 2Cl-

Thanks dear...