Final answer:
To balance redox reactions using the ion-electron method, assign oxidation states, separate the reaction into oxidation and reduction half-reactions, balance the number of electrons, and then combine the half-reactions, ensuring that both the charge and the mass are balanced.
Step-by-step explanation:
How to Balance Redox Reactions Using Ion-Electron Method
To balance redox reactions using the ion-electron method, also referred to as the half-reaction method, follow these basic steps:
Write the unbalanced chemical equation for the reaction, showing the reactants and the products.Assign oxidation states to all atoms in the reactants and products to determine which atoms change oxidation state.
Write separate equations for oxidation and reduction, indicating the number of electrons accepted or donated by each atom.Multiply these half-equations by appropriate coefficients to ensure that both contain the same number of electrons.
Balance the charge by adding electrons to the more positive side of one half-reaction or the other to achieve charge balance.Combine the balanced half-reactions, ensuring that the number of electrons lost in oxidation equals the number gained in reduction.
In the case of reactions in basic solution, add an equal number of OH- ions to both sides of the equation to balance the charge, then combine H+ and OH- to form water, and cancel out any water molecules appearing on both sides.
Always check your final equation to ensure that both mass and charge are balanced. The half-reaction method is versatile and particularly suitable for balancing reactions in aqueous solutions.