chemical equilibrium problem pls help reply soon plss

[dragonlady90]

1. The problem statement, all variables and given/known data
A sol'n contains Cu+2(aq) and Zn+2 ions each at a con'c of 0.1M. Hydrogen sulphide gas is bubbled up into sol'n and dissociates having an initial con'c of 0.1M. Whats the pH of the final solution? Will any precipate form?
I dont know how to start the problem. Pls help me and reply soon.

2. Relevant equations



3. The attempt at a solution

[Borek]

H2S is a weak diprotic acid. Differences between both dissociation constants are large enough to calculate each dissociation equilibrium separately. You have to check what the pH is (it i will be solely governed by the first dissociation step), use this pH value to calculate S2- concentration, and check if this concetration will be large enough for precipitation (hint: look for Kso values).

For more details see this page on the pH of polyprotic substance (http://www.chembuddy.com/?left=pH-calculation&right=pH-polyprotic-simplified) calculation.

Borek
--
pH calculator (http://www.chembuddy.com/?left=BATE&right=pH-calculator)

[dragonlady90]

thanks for your reply Borek,

can u tell equation of this equilibrium problem so that i can solve it further. THat would be really helpful.
Once again, thanks for your reply.

[Borek]

All equations that you need to calculate pH of the solution and S[sup]2-[/sup concentration are listed on my site.

[chemisttree]

Are you still having problems with this question?