This is an oxidation-reduction (redox) reaction:

2 NV + 4 e- → 2 NIII (reduction)

2 O-II - 4 e- → 2 O0 (oxidation)

Mg(NO3)2 is an oxidizing agent, Mg(NO3)2 is a reducing agent.

## Input interpretation

Mg(NO3)2      →        Mg(NO2)2       +         O2

Magnesium nitrate                                        oxygen

## Balanced equation

Balance the chemical equation algebraically:

Mg(NO3)2      →        Mg(NO2)2       +         O2

Add stoichiometric coefficients,c1 to the reactants and products:

c1Mg(NO3)2            →       c2Mg(NO2)2     +      c3O2

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

Mg:   c1= c2

N:      2c1= 2 c2

O: 6c1 =  4 c2+   2c3

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:

c1= 1

c2=1

c3 = 1

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