Re: making tin(II) chloride

Arsea wrote:
> I was trying to make stannous chloride, by dissolving excess tin metal
> into 30% hydrochloric acid. I'm using a flask with a small outlet to
> avoid air oxidation of the stannous ion. The solution I make is deep
> purple color, however my references say SnCl2 solutions are clear.

Solid SnCl2 is colorless. Stannous chloride produces a milky white
suspension in water due to its hydrolysis, however strongly acidic
solution should be colorless.

>The
> tin and HCl I'm using are industrial grade and so I'm wondering if the
> color its due to an impurity that is strongly colored.

Though this might be relevant in you case (one can safely rule out gold
in your HCl), but traces of gold produce a purple coloration in the
presence of stannous and stannic chloride. I don't recall any metal
imparting a deep purple color if present in traces in HCl solution
(cobalt could be the culprit if large amount is present); Is the tin
metal pure? But finally Zigoteau's hypothesis on the color due to
colloidal particles sounds correct.

>The reaction
> essentially goes to completion, with final HCl concentration < 0.3M.

Does adding concentrated nitric acid remove the blue coloration? If you
are inclined to further experimenting, try adding some activated
charcoal to check if the purple color is removed/altered on shaking.

.