Question

Magnesium is a reactive metal and burns in air with a brilliant, bright white light. Explain what would happen if you used a carbon dioxide fire extinguisher in this instance.

Answer 1

The reaction of Mg and oxygen (in the air, we have oxygen) is the following:

$2Mg+O_2\to2MgO.$

If we use carbon dioxide (CO2) to react with magnesium oxide (MgO), we can see that this compound would continue to burn. This is because the reactivity series of Mg is above the reactivity of carbon and this compound can take the oxygen from carbon dioxide to react.