In the reactions below identify the species being oxidized and reduced.?

a)
The equation should be 2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g) instead.
Na(s) is oxidized because the oxidation number of Na increases from 0 (in Na) to +1 (in NaOH).
H₂O(l) is reduced because the oxidation number of H decreases from +1(in H₂O) to 0 (in H₂).

b)
CO is oxidized because the oxidation number of C increases from +2 (in CO) to +4 (in CO₂).
I₂O₅(s) is reduced because the oxidation number of I decreases from +5 (in I₂O₅) to 0 (in I₂).