Burning of coal and magnesium
Burning of coal (a) and magnesium (b) are rapid oxidation processes while rusting of iron is a slow oxidation process.
Since years, we have been burning coal to get heat. We also know that for burning of coal we need supply of fresh air. What happens when coal burns? The oxygen from the air reacts with carbon in coal. We can represent this reaction by the chemical equation as follows:
C + O2 CO2 (g)
Carbon dioxide is the product. If sufficient supply of fresh air is not available, the reaction may be as follows:
2C + O2 2CO (g)
Carbon monoxide is the product. Both the products, CO2 and CO, being gases escape into the atmosphere.
Another common experience is burning of magnesium wire, which is popular in the fireworks.
2Mg + O2 2MgO