help help...check my mistake and correct it?

Question

Reaction (1) to (4) can occur in the industrial conversion of ammonia into nitric acid.

Note: I would denote the oxidation number as ON:

Which one of these reactions shows the greatest change in the oxidation number of nitrogen?

(1) 4NH3 + 5O2 ---> 4NO + 6H2O
The ON of N in 4NH3 is -3, and the N in 4NO is +2, correct?

(2) 3NO2 + H2O ---> 2HNO3 + NO
The ON of N in 3NO2 is +4, the ON of N in 2HNO3 is +6 and the ON of N in NO is +2, correct?

(3) 2NO + O2 --> 2NO2
The ON of N in 2NO is +2 and the ON of N in 2NO2 is +4, correct?

(4) 4NH3 + 6NO --> 5N2 + 6H2O
The ON of N in 4NH3 is -3, the ON of N in 6NO is +2 and the ON of N in 5N2 is 0, correct?

however, my answer is (2) but the correct answer is (1)...please correct my mistakes from the above workings and show me your workings on how you calculate out that the greatest change in the oxidation number of nitrogen is in (1)..thanks

Answer 1

In equation 2, the oxidation number of N is +FIVE, so the CHANGE is (in absolute terms) 3. In the first equation, the change is FIVE.