Final answer:
In balancing a redox reaction in a basic aqueous solution, OH- ions may be added to neutralize excess H+ ions.
Step-by-step explanation:
In balancing an equation for a redox reaction that occurs in a basic aqueous solution, you may need to add OH- ions to the equation. This is because in a basic solution, H+ ions are neutralized by OH- ions to form water (H2O). By adding OH- ions to both sides of the equation, you ensure that the overall charge is balanced and eliminate any excess H+ ions.