For each of the following redox reactions in the, identify the oxidizing agent and the reducing agent.
2Na(aq)+2H2O(l)→2NaOH(aq)+H2(g)
C(s)+O2(g)→CO2(g)
2MnO−4(aq)+5SO2(g)+2H2O(l)→2Mn2+(aq)+5SO2−4(aq)+4H+(aq)