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### 3A Determining reduction vs oxidation

Posted: Tue Feb 20, 2018 8:56 pm
I am having trouble identifying the reducing and oxidizing agent in equations such as 3a in the homework?

### Re: 3A Determining reduction vs oxidation

Posted: Tue Feb 20, 2018 9:13 pm
In determining the oxidized element and reduced element, you look at which element's oxidation number becomes more positive (oxidized) and which one becomes more negative (reduced). For instance, in 3a, the reaction given is
Cl2 + S2O3 2- -> Cl - + SO4 2-.
Chlorine is the reduced element (AKA oxidizing agent) because it goes from an oxidation number of 0 (an element in its pure non-ionic state will always have an oxidation number of 0) to -1. Thus, it gained an electron when the reaction occurred. Keep in mind that this reaction isn't balanced, so we would technically have 2 Cl- ions, for a net total of two electrons gained by chlorine ions. This leaves S203 to be oxidized (the reducing agent).

### Re: 3A Determining reduction vs oxidation

Posted: Tue Feb 20, 2018 9:14 pm
The oxidizing agent is the reactant that is oxidizing its fellow reactant by taking its electrons. Therefore, the oxidizing agent itself has a reduced product.
The reducing agent is the reactant doing the reducing to something else by giving away its own electrons, therefore making it the oxidized product.

oxidizing agent=reduced product
reducing agent=oxidized product

### Re: 3A Determining reduction vs oxidation

Posted: Wed Feb 21, 2018 10:06 am
I always like to use OIL RIG (Oxidation Is Losing, Reduction is Gaining) to remember which elements are being oxidized and reduced. Once you know this, remember that the element being oxidized is the reducing agent and the element being reduced is the oxidizing agent.

### Re: 3A Determining reduction vs oxidation

Posted: Wed Feb 21, 2018 4:34 pm
Lorie Seuylemezian-2K wrote:I am having trouble identifying the reducing and oxidizing agent in equations such as 3a in the homework?

What's been easiest for me is to think that the oxidation state goes down-- i.e., is being reduced-- in the elements that are being reduced (the oxidizing agents).
So if the oxidation number goes from (+7) to (+2), that species is being reduced. The number is reducing, it is gaining electrons, and it is the oxidizing agent. Hope this gives you a few ways to think of it :)