Hard Chemistry question...precipitates 2?

Question

I need to write a balanced net ionic equation describing each of the following reactions:

(a) Precipitation of tin(IV) sulfide with H2S

(b) The confirming test for tin

(c) The conmfirming test for copper.

Thank you for your help!!

Answer 1

(a) Precipitation of tin(IV) sulfide with H2S

Sn+2  & 2 H2S --> SnS2  & 2H+

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(b) The confirming test for tin

this reference describes the test for tin that I use:

http://www.wiredchemist.com/chemistry/in...

your first reaction Iron reduces Sn+4 to Sn+2:

Sn4+(aq) + Fe(s) → Sn2+(aq) + Fe2+(aq)

this is the usual ID test, making a white ppt of Hg2Cl2:

Sn2+(aq) + 2HgCl2(aq) → Sn4+(aq) + Hg2Cl2(s) + 2Cl-(aq)

When there is a lot of Sn+4 converted to Sn+2, the Hg2Cl2 produced above continues to be reduced even furthe to Mercury metal:

Sn2+(aq) + Hg2Cl2(s) → Sn4+(aq) + 2Hg(l) + 2Cl-(aq)

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(c) The conmfirming test for copper.

Cu+2 & 4 NH3 --> [Cu(NH3)4]+2