When lightning strikes, nitrogen molecules, N₂, and oxygen molecules, O₂, in the air react to form nitrates, NO₃^1-, which come down in the rain to help fertilize the soil. Is this an example of oxidation or reduction?

(a) The formation of nitrates is an example of reduction.

(b) The formation of nitrates is an example of oxidation.

(c) Both. The nitrogen is oxidized as it reacts with the oxygen while the oxygen is reduced.

(d) Neither. Although the bonds of both the N₂ and O₂

molecules are broken to form the NO₃^1-, neither oxidation nor reduction occurs.