Final answer:
Add OH- ions to both sides of a redox reaction when balancing in a basic solution, to neutralize H+ ions, combine them into water, and balance the overall charge and atoms.option d)) Add OH- ions to the reactants
Step-by-step explanation:
When balancing a redox reaction in a basic solution, you should add OH- ions to both sides of the equation to neutralize any H+ ions present from the balancing in acidic conditions.
This is done because basic solutions contain excess hydroxide ions and it's unlikely that H+ ions will be present in significant quantities. After the addition of OH- ions, any H+ ions (if they were added during the balancing for acidic conditions) combine with the OH- ions to form water (H2O), which can be balanced by adding or removing water molecules as necessary. This process also ensures that the overall charge is balanced across both sides of the reaction.