help please: oxidation/reduction

[sdnstud]

---

Members don't see this ad.

This is a problem from test 3 columbia review:

given: 2 NO(g) + O2 (g) --> 2 NO2(g)

This reaction involves which of the following:
a) oxidation of nitrogen and reduction of oxygen gas
b) oxidation of nitrogen and oxidation of oxygen gas
c) reduction of nitrogen and oxidation of oxygen gas
d) reduction of nitrogen and reduction of oxygen gas

my answer is A. but the answer key says C. anyone wanna explain why?

 

[DaveinDallas]

This is a problem from test 3 columbia review:

given: 2 NO(g) + O2 (g) --> 2 NO2(g)

This reaction involves which of the following:
a) oxidation of nitrogen and reduction of oxygen gas
b) oxidation of nitrogen and oxidation of oxygen gas
c) reduction of nitrogen and oxidation of oxygen gas
d) reduction of nitrogen and reduction of oxygen gas

my answer is A. but the answer key says C. anyone wanna explain why?

Ok, this is worth exactly what you're paying for it. I may be way off here, but what the heck, no one else has tried and I'll at least give the thread a starting point for argument...

The rxn is removing oxygen from the NO in an intermediate step and adding O2. So according to one definition of reduction - which is losing an oxygen or gaining a hydrogen, NO is reduced in the intermediate step when the O goes away. One definition of oxidation is the loss of electrons which happens when the N and O2 are bonded. Does that sound correct?

Or it could be that the answer key is wrong....

 

[Scottish Chap]

This is a problem from test 3 columbia review:

given: 2 NO(g) + O2 (g) --> 2 NO2(g)

This reaction involves which of the following:
a) oxidation of nitrogen and reduction of oxygen gas
b) oxidation of nitrogen and oxidation of oxygen gas
c) reduction of nitrogen and oxidation of oxygen gas
d) reduction of nitrogen and reduction of oxygen gas

my answer is A. but the answer key says C. anyone wanna explain why?

It's easier to remember that oxidation is loss of electrons (and gain of oxygen in this case), but the thing that's 'oxidizing' it's always REDUCED itself (in this case, the latter is O2). Hope that helps.

 

[inshanesworld]

Two possible mechanisms

i) 2 NO ---> N2O2 (fast, equilibrium)

O2+ N2O2 -------> 2 NO2 (slow)

ii) NO + O2 -------> NO2 + O (slow)

NO + O --------> NO2 (fast)


Either way, if you do the lewis structures and find the formal charges etc you will see that the nitrogen gains an electron in the process from the oxygen and thus the nitrogen is reduced and oxygen is oxidized.

 

[liverotcod]

A is correct. The nitrogen in NO goes from +2 to +4, losing two electrons and being oxidized. Oxygen gas goes from 0 to -2, gaining two electrons and being reduced.

Check the errata.

 

[CanIMakeIt]

A is correct. The nitrogen in NO goes from +2 to +4, losing two electrons and being oxidized. Oxygen gas goes from 0 to -2, gaining two electrons and being reduced.

Check the errata.

That is the correct solution ....... or at least that is what I concluded.

 

[IllinoisStudent]

anyone know a case where oxygen gets oxidized? 😕

formation of ozone?

 

[liverotcod]

anyone know a case where oxygen gets oxidized? 😕

formation of ozone?

I should think it would only be in some kind of compound with fluorine - that's the only atom more electronegative. I don't know of any such compounds, but maybe something like FO3?, fluorate? by analogy to chlorate.

 

[willthatsall]

I should think it would only be in some kind of compound with fluorine - that's the only atom more electronegative. I don't know of any such compounds, but maybe something like FO3?, fluorate? by analogy to chlorate.

I think there is an OF2, but yeah, something with F is the only situation I can think of.