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# Writing a half equation for an oxidation reaction? Watch

1. I absolutely suck at writing these equations, Im ok determining the oxidation numbers and such like of elements in a compound, I can do those fine but when it comes to these I really struggle. If anyone could offer some assistance please?

Its question 10 that Im stuck with, I've done all the other questions it's just that one Im stuck with.

Reducing agent - SO?

Oxidising agent - H?

Writing the half equation - not even got a clue

Appreciate any help appreciated what so ever, even the tiniest little bit. Thanks.
x

Its question 10 that Im stuck with, I've done all the other questions it's just that one Im stuck with.

Reducing agent - SO?

Oxidising agent - H?

Writing the half equation - not even got a clue

Appreciate any help appreciated what so ever, even the tiniest little bit. Thanks.
The reducing agent is SO2 and the oxidising agent is CuCl2
You can work this out using oxidation numbers(see the attached image). To help decide what is the reducing/oxidation agent I just think of it like this if something is being oxidised it is releasing e-s, so something else must pick up these e- and become reduced. Therefore, the reagent that is itself oxidised is a reducing agent.

For the half equation you can see using oxidation numbers SO2 is oxidised because of this I would first write out the things in black.
After writing this you can see:
1. There are more oxygen atoms on the RHS
2. There is a net 4- charge in the RHS and there is no overall charge on the LHS

Because of this we need to add some other reactant to sort the above problems out. From the question you know that the copper(II)chloride is in a solution so there is some water around and my own general rule is when I need some oxygen I think H2O. So at this point I added the things in green to solve the issue with charges and number of oxygen atoms.
( I know you could be lazy and look at the overall equation for this part but in the exam they may not always be this kind)

The above is my attempt at the answer and sorry about the dodge rotation of the image my iPad would not let me write on the image unless I had it rotated this way :s

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Updated: April 18, 2013
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