Justify that the following reactions are redox reactions:
Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g)
Let us write the oxidation number of each element involved in the given reaction as:
In Fe2O3, Fe = + 3 and O = -2
In CO, C = + 2 and O = -2
In CO2, C = + 4 and O = -2
In Fe, Fe = 0
Here, the O.N. of Fe decreases from + 3 in Fe2O3to 0 in Fe i.e. Fe2O3 is reduced to Fe. On the other hand, the O.N. of C increases from + 2 in CO to + 4 in CO2. Hence, the given reaction is a redox reaction.