Stannous Chloride is a white to off-white flake or crystalline (sand-like) solid. It is used in making dyes and pharmaceuticals, and as a tanning agent.
SnCl2 has a lone pair of electrons, such that the molecule in the gas phase is bent. In the solid state, crystalline SnCl2 forms chains linked via chloride bridges as shown.
Ferric Iron is reduced to ferrous iron by stannous chloride in the present of Hydrochloric acid at a temperature of 70-900C. The excess stannous chloride is removed by the addition of mercuric chloride.