# Thread: Calculator; NO2 + H2O => HNO3 ?

1. I'm doing some research (library and a bit of internet searching) on the subject NO2 and N2O4

I've hit a snag, question; how do you proceed with making liquid N2O4 into nitric acid. I am uncertain of the energy and entropy of the reactions. Several reactions have been suggested to me:
1. Add liquid N2O4 to distilled water, this should result in N2O4 + 2 H2O => 2 H2NO3 => 2 H+ + 2HNO3-
2. Naa, that wont work, but if you heat it it will react as above
3. Naah, you need a catalyst as well, palatinum should work
4. Naah, you need to add it to hydrogen peroxide which per gram costs a fortune so it's not worth it. (H2O2 is only sold in 3% solution in EU, 500 g of this costs 2 eur and {0,03*500 g =15 g, 2 eur / 0,015 Kg = 113 eur/Kg, i.e. a small fortune) N2O4 + 2 H2O2 => 2 H2NO3 + O2 => 2 HNO3 + H2 + O2
So now I need help, which of the above is true?

2.

3. dear heres, am confused with this reaction. According to this reaction, better to say dissolution of NO2 or itz dimer N2O4 in water oxidation of N is happening. As in both N2O4 or NO2 the oxidation number of N is +4, whereas it is + 5 in HNO3. So far I know the oxidation number of nonmetal in itz oxide remains the same when it is dissolved in water to produce relevant acid. So from this context oxide of HNO3 should be N2O5 where the oxidation number of N is +5, same as in N in HNO3. that means the desired reaction should be : N2O5+ H2O = 2HNO3.
Furthermore other oxides of N like N2O3 having on oxidation number +3 will produce an nitrogenous acid where the oxidation number of N will remain +3, i.e, HNO2.
N2O3+H2O = 2HNO2
Interesting feature of NO2 is that it's oxidation number +4 lies in between +3 and +5,( average of 3 & 5 is 4) i.e, in between N2O3 and N2O5 which produce respectively HNO2 & HNO3. the fact is that while NO2 or it's dimer N2O4 is dissolved they produce both HNO2 & HNO3.
REACTION : 2NO2+H2O = HNO2 +HNO3 OR , N2O4 +H2O = HNO2 +HNO3.
So, if you need to produce HNO3 alone from liq NO2 or N2O4 by dissolving then in water you need to rise the oxidation state of N from +4 to +5 level using some oxidant as you have chosen H2O2 which will oxidise NO2 to N2O5 either or HNO2 to HNO3.

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