Question- Why should a magnesium ribbon be cleaned before burning in air?
Answer-
A magnesium ribbon is cleaned before burning in air to remove the protective layer of magnesium oxide that forms on its surface over time. This oxide layer acts as a barrier, preventing the magnesium metal from reacting readily with oxygen when ignited.
By cleaning the ribbon with sandpaper, we ensure that the underlying magnesium metal is exposed to air, allowing it to react more vigorously when burned.
When a cleaned magnesium ribbon is burned in air, it reacts with oxygen to produce magnesium oxide, as indicated by the dazzling white flame and the formation of a white powder.
The reaction can be represented by the following balanced chemical equation-
2Mg + O₂ → 2MgO
This equation illustrates that magnesium (Mg) combines with oxygen (O₂) from the air to form magnesium oxide (MgO), releasing a significant amount of light and heat in the process. Cleaning the magnesium ribbon is a crucial step to ensure the reaction proceeds efficiently and safely.
