What is the oxidation number of nitrogen (N) in HNO2?

2 Answers
Apr 3, 2018

#N^(+3)#

Explanation:

Well look at the just the ion, the nitrite ion:
#NO_2^(-1)#

Is that a plausible statement?

Because we know that #HNO_3# has a net charge of 0, and #H# has a charge of #+1#, therefore the Nitrite ion must have a charge of #+1#

To further simplify, we know that oxide ion has a charge of #-2# or #O^(-2)#:

#(NO_2)^(-1)#

#(N(O_2^(-2)))^(-1)#

That gives us a charge of #-4# on just the oxide ions, to balance that charge to #-1#, the charge on N must be #+3#

#N^(+3)#

Apr 3, 2018

#+3#

Explanation:

We have nitrous acid, with a chemical formula of #HNO_2#. It is a neutral molecule as well.

Oxygen is more electronegative in this case, and so possesses an oxidation state of #-2#. There are two oxygens here, and so the total charge is #-2*2=-4#.

Hydrogen usually possesses an oxidation state of #+1#, and it does here as well.

Let #x# be the oxidation state of nitrogen.

We got:

#1+x+(-4)=0#

#x-3=0#

#x=3#

So, nitrogen here has an oxidation state of #+3#.