deciding which is oxidized/reduced

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deciding which is oxidized/reduced

Postby Kim » Mon Feb 13, 2017 9:16 am

P. 162 in the course reader, #8 in winter 2016 midterm:
"a standard electrochemical cell is made by placing a silver electrode into a 1.0M Ag+ solution and a cadmium electrode into a 1.0 M Cd2+ solution.
What is the redox reaction and what is the maximum potential produced?"
how would you know which is being oxidized and reduced if this is all the information they give? couldnt it be either one?

(the answer is that cadmium is being oxidized and silver is being reduced)

Cindy Flores 2C
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Re: deciding which is oxidized/reduced

Postby Cindy Flores 2C » Mon Feb 13, 2017 10:35 am

The best way to determine which half reaction is being oxidized or reduced is to take note of the standard reduction potentials for each half reaction. It's not given in the problem but Professor Lavelle has said before that we would be given a table with those potentials when needed. Furthermore, in the problem you picked cadmium is chosen to be oxidized because once the sign of the potential changes from negative to positive those two potentials create a positive voltage.

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Re: deciding which is oxidized/reduced

Postby Chem_Mod » Mon Feb 13, 2017 10:36 am

By looking at the standard reduction potential chart, the one with more positive value will be the stronger oxidizing agent and will tend to gain electron, vice versa

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