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Equilibrium Lab

1. Homework Statement

COCL4 + 6H2 <=> Co(H20) +4CL

blue <=> pink

Question: Add a very small amount of AgNO3 to test tube #6. Stopper the test tube and shake.

The solution in test tube turned pink, so I interpreted that as a shift to the products. Also, a precipitate (proper term? a solid was present...) formed.



3. The Attempt at a Solution


Now I have to offer an explanation for why this occurred. It seems as though the Ag+ is slightly soluble in Cl-, and the Cl is found on the product side, so was the Cl consumed somehow and thus produced CoCl42-?

To me that doesn't seem reasonable.

EDIT: I somehow thought myself into a circle, because CoCl42- wouldn't have been produced, for if it had the solution should have turned blue right? I'm fairly sure my explanation should hinge on the fact that Ag+is only slightly soluble with Cl-, but I don't want to go off on a tangent either, so if I'm horribly misguided please advise.
 
Last edited:
I'm using this thread as a sort of running journal. If that is unacceptable, for some reason, please do inform me.

New equation:

2AgNO3(s) + 6H2O(al) + 2CoCl4(al)2- <=> Co(h2O)6(al)2+ + 8Cl(al)- + Co(NO3)2 (al) + 2Ag (s) + energy

How many different ways can the equilibrium be shifted to the right? i.e. Removal of product, addition of reactant and removal of energy.
 
The charges on the new equation don't balance. Looks like more Co(H20)6 (al) 2+ will have to be produced, and if that holds true then I can explain the colour change.
 

Borek

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None of the reaction you have written so far is correct.

What happens in the solution containing Ag+ and Cl-?
 
None of the reaction you have written so far is correct.

What happens in the solution containing Ag+ and Cl-?

CoCl42- + 6HOH + 4AgNO3(s) <=> Co(HOH)62+ + 4AgCl(s) + 4NO3- + energy

Is this equation correct?
 

Borek

Mentor
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Much better, but not necesarilly correct.

AgNO3 is well soluble. And no need to put some fancy looking dihydrogen monoxide HOH in the equation :wink:
 
Doesn't HOH = H2O? I just found it easier to type HOH, so I did. Thanks for the help.
 

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