Balance each half-reaction with respect to hydrogen by adding, for each deficient hydrogen, one H₂O molecule to the side deficient in H and then one OH^- ion to the other side (one H₂O minus one OH^- gives one H atom so the net effect in doing so is to add one hydrogen to the H-deficient side).

In this case, the oxidation half-reaction needs one H on the right side to balance hydrogen atom, so one OH^- is added to the left and one H₂O to the right (H^- deficient side). Combine the like terms.