1. Nov 14, 2006

### PhysicsNoob88

Hello, I just have a question regarding this problem. Please tell me if its correct.

I have to identify the substance oxidized, the substance reduced, the oxidizing agent, and the reducing agent.

http://xs109.xs.to/xs109/06462/chem..png [Broken]

For the first one This is what I believe:

H2O2 = substance oxidized
H202 = Oxidizing agent
H2CO = substance reduced
H2CO = reducing agent

2nd one I believe its:

2CrO3 = substance reduced
2CrO3 = substance oxidized
6HI = oxidizing agent
6HI = substance reduced

Last edited by a moderator: May 2, 2017
2. Nov 14, 2006

### geoffjb

Notice how in the first example, you've named the substance that was oxidized to be the oxidizing agent. In the second example, you named the substance that was reduced to be the oxidizing agent. Not only that, but you said chromium oxide was both reduced and oxidized.

Last edited by a moderator: May 2, 2017
3. Nov 14, 2006

### PhysicsNoob88

oh whoops.

It was supposed to be:

2CrO3 = substance oxidized
2CrO3 = Oxidizing agent
6HI = substance reduced
6HI = reducing agent

See this problem was supposed to be an example to a problem set assigned but the answers were cut off. Trying to understand this problem so i can use it to answer the others. Any help would be greatly apperciated.

4. Nov 14, 2006

### geoffjb

Remember that a reducing agent reduces, and an oxidizing agent oxidizes. An agent that reduces can not in itself be reduced.

Draw out each half-reaction (including electron transfer) to determine which substance is oxidized, and vice versa.

I'd suggest taking a look here:
http://en.wikipedia.org/wiki/Redox#Oxidizing_and_reducing_agents

If you are still confused, post again after having attempted those questions again.

5. Nov 14, 2006

### PhysicsNoob88

I gave it another try, I think the first one may be right but I found the 2nd one to be harder (but who knows they might both be wrong )

#1

H2H02 = Reducing agent,because it is oxidized.
H2CO = Oxidizing agent because it gains an election.
H2CO2 = substance oxidized because it gains an electron.
H20 = Substance reduced ? Not really sure.

#2

6HI = Reducing agent because it losses hydrogen?
2CrO3 = Oxidizing agent
Cr2O3 = Substance oxidized. Lose an electron.
3H2O = substance reduced

6. Nov 14, 2006

### PhysicsNoob88

Anyone please? I have problem set due tomorrow at 10 AM EST time.. I really need these question verified so i can do the rest. Thanks!

7. Nov 14, 2006

$$H_{2}CO$$ : reducing agent

$$H_{2}O_{2}$$: oxidizing agent

$$2CrO_{3}$$: oxidizing agent

$$6HI$$: reducing agent

8. Nov 15, 2006

### PhysicsNoob88

^Thanks a bunch.

So would that make

H2C02 - substance oxidized
H20 - substance oxidized

&

Cr2o3 - substanced oxidized
3H20 - substanced reduced

Thanks!