Table of contents

This is an oxidation-reduction (redox) reaction:

NV + 8 e- → N-III (reduction)

4 O-II - 8 e- → 4 O0 (oxidation)

Word equation

nitric acid + water → ammonia + oxygen

Input interpretation

HNO3 + H2O → NH3 + O2

Nitric acid water ammonia oxygen

Balanced equation

Balance the chemical equation algebraically:

HNO3 + H2O → NH3 + O2

Add stoichiometric coefficients, c1, to the reactants and products:

c1 HNO3 + c2H2O → c3 NH3 + c4O2

Set the number of atoms in the reactants equal to the number of atoms in the products for H, N and O:

H: c1 + 2c2 = 3c3

N: c1 = c3

O: 3c1+ c2 = 2c4

Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c1 = 1 and solve the system of equations for the remaining coefficients:



c3 = 1 


Substitute the coefficients into the chemical reaction to obtain the balanced equation:


HNO3 + H2O → NH3 + O2

#BBD0E0 »