, in the reaction where silver is oxidized and zinc is reduced, the following occurs:
- Silver ions (Ag+) gain one electron each and are reduced to silver atoms (Ag).
- Zinc atoms (Zn) lose two electrons each and are oxidized to zinc ions (Zn2+).
The half reactions are:
- Reduction: Ag+ + e- → Ag
- Oxidation: Zn → Zn2+ + 2e-
To balance the half reactions, you need to make sure that the number of atoms and the net charge are the same on both sides of each equation. You can do this by adding coefficients, water molecules, hydrogen ions, or hydroxide ions as needed, depending on the type of solution (acidic or basic).
For this reaction, the half reactions are already balanced for atoms, but not for charge. To balance the charge, you need to multiply the reduction half reaction by 2, so that the total number of electrons lost and gained is equal. The balanced half reactions are:
- Reduction: 2Ag+ + 2e- → 2Ag
- Oxidation: Zn → Zn2+ + 2e-
To get the overall balanced equation, you need to add the two half reactions and cancel out any common terms. The overall balanced equation is:
- 2Ag+ + Zn → 2Ag + Zn2+