Normality for Redox Reaction

[toothfary25]

I've been reviewing normality (for some reason, I didn't learn this technique in Chem) and I have a good grasp on acid-base applications, but the redox reactions are harder to find info on. This problem below seems simple but I'm just wondering if someone could elaborate on the theory behind it:

Reaction of 2.5M dichromate:
Cr2O72- goes to Cr3+

What would be solution Normality if reaction goes to completion?
Answer: 7.5 N

Explanation: Electron change is 3 e-s since chromium goes from a 6+ to a 3+ oxidation state.

Okay, so that's relatively clear... but I guess I just don't really know how the theory works behind normality with redox reactions. Do you just always look for the change in electrons and use that as your multiplying factor? Are there any other applications of normality in redox rxns besides the one presented here that I need to know?

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[rals]

sometimes you just have to learn things from the explanations of answers to questions you don't know. I didn't know that either, but it makes sense when they explain it. It makes sense to you, right?

I don't think you should worry about there being other applications of normality in redox reactions. if you understand this, you should be ok with other similar questions.

best of luck.

 

[jackbauer!]

i was confused by the same question..... i, also, was never taught this in general chem. i just bit the bullet and took it for what it was worth...

jb!

 

[toothfary25]

Okay, if you guys are on the same page then I'm fine with it too! I just was like - where did this question come from??? But yeah, I won't sweat all the theory and junk behind it (I have a tendency to do that). Thanks!