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Topic: Balancing redox reaction with oxidation #s??  (Read 2789 times)

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Offline r4bbit_

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Balancing redox reaction with oxidation #s??
« on: April 09, 2008, 10:15:03 PM »
Hi all, I am learning about balancing chemical reactions using redox oxidation #s, and I am having trouble with questions with this format:

-one side of the reaction has more of the redox elements than the other side

e.g.

K2Cr2O7+3HCl -> CrCl3+KCl + Cl2 +H2O

What I did so far was finding the RA (reducing agent) and OA, i found out that obviously the Cr +6 reduced to Cr +3 and Cl -1 oxidized 0 (Cl2).

But I am still having trouble, because even though Cl undergoes redox, what about the other Cl-containing compounds like KCl and such, do I have to balance the Cl of those with my HCl??

Offline Borek

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Re: Balancing redox reaction with oxidation #s??
« Reply #1 on: April 10, 2008, 03:40:45 AM »
They are just spectators. Try to balance net ionic reaction equation first, so that they will not interfere, then you may convert net ionic to molecular by adding enough spectators to make total charge on each side of the equation 0.

If you prefer to not use net ionic, you may add HCl at will, just remember to cancel it (if it happens to be on both sides of equation) once everything is in place.
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