For each reaction:
- Identify the redox pairs. For example, Permanganate ions and Manganese ions are a pair.
- Write the half equations for each redox pair.
- Combine the half equations to give an overall (net) equation.
- Use oxidation numbers to justify that these are indeed redox reactions. In the first experiment, focus on the oxidation numbers of manganese and iron. In the second experiment, look at the oxidation number of chromium.