Question

Role of stannous chloride and mercuric chloride in the estimation of iron

Answer 1

Answer:

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

Explanation:

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-

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