02 (s) + pb(s) — pbo2(s) find the reduced and oxidized reactants

Oxygen is oxidizing gent and itself get reduced while lead is reducing agent and itself get oxidize.

Explanation:

Chemical  equation with oxidation state:

O⁰₂(s)  +  Pb⁰ (s)    →  Pb⁺⁴O₂⁻²(s)

Oxidizing agent:

Oxidizing agents, oxidize the other substance and itself get reduced. They can be identify by just looking the oxidation state. If oxidation state is decreased on the right side it means substance gain the electron and get reduced.

Reducing agent:

Reducing agents, reduce the other substance and itself get oxidize. They can be identify by just looking the oxidation state. If oxidation state is increased on the right side it means substance lose the electron and oxidation state increased.

In given chemical equation, oxygen and lead were in neutral form they react and form lead dioxide. In this product oxygen is oxidizing gent and itself get reduced and oxidation state change from 0 to -2 while lead is reducing agent, itself get oxidize and oxidation state change from o to +4.