Redox question

[shaggybill]

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Can anyone explain why the answer is D?

In the answer, it states that the oxidation numbers of neither hydrogen nor oxygen change in this reaction, but it looks to me like the the H goes from +2 to +1. As for the oxygen, I guess I'm confused as to which one to look at on the products side.

Thanks!

 

[BerkReviewTeach]

Can anyone explain why the answer is D?

In the answer, it states that the oxidation numbers of neither hydrogen nor oxygen change in this reaction, but it looks to me like the the H goes from +2 to +1. As for the oxygen, I guess I'm confused as to which one to look at on the products side.

Thanks!

H has only one electron, so it can never be a +2. You need to divide the +2 for both hydrogens by 2 (because there are two hydrogens in water) to get a value of +1 each.

Also, what may help, is that you get 2 HNO3 molecules on the product side of the equation.

3 NO2 + 1 H2O -> 2 HNO3 + 1 NO

Other than the oxidation state of H being incorrect, the rest is fine.

 

[shaggybill]

Thank you for the reply. I still dont understand the oxygen though. How can I know which oxygen on the products side is the one to use when comparing oxidative numbers?

EDIT: Never mind, I figured it out as soon as I submitted this post. 🙂