Final answer:
To balance a reaction in an acidic solution, use H₂O(l) for oxygen balance and H⁺(aq) to balance hydrogen and charge; avoid OH⁻ ions which are not common in acidic environments.
Step-by-step explanation:
When balancing a redox reaction in an acidic solution, you can use H₂O(l) to balance the oxygen atoms and H⁺(aq) ions to balance the hydrogen atoms and the overall charge. For balancing reactions in an acidic environment, OH⁻(aq) ions are usually not appropriate as they are not common in such solutions. An example of this process is adding enough H⁺ ions to equilibrate the charges on both sides of the equation. If a reaction is carried out in a basic solution, you would add OH⁻ ions to both sides of the equation to neutralize any H⁺ ions, followed by simplifying the reaction.