International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

Which catalyst is used in the decomposition of hydrogen peroxide to produce oxygen?

1. Copper(II) oxide

2. Zinc oxide

3. Manganese(IV) oxide

4. Iron(III) oxide

The correct answer is: Manganese(IV) oxide

Manganese(IV) oxide is a well-known catalyst used in the decomposition of hydrogen peroxide (\(H_2O_2\)) to produce oxygen gas. This reaction involves breaking down hydrogen peroxide, which tends to decompose into water and oxygen spontaneously but very slowly under normal conditions. The presence of manganese(IV) oxide significantly accelerates this process, facilitating the release of oxygen at a much faster rate. Manganese(IV) oxide acts by providing an alternative reaction pathway with a lower activation energy, allowing the hydrogen peroxide molecules to decompose more readily. The catalyst itself does not get consumed in the reaction, which is a key property of catalysts. As a result, it can be used repeatedly in this reaction, making it an effective choice for industrial and laboratory processes involving the release of oxygen from hydrogen peroxide. The other catalysts listed do not exhibit the same level of effectiveness in this particular reaction or are not typically recognized for facilitating the breakdown of hydrogen peroxide.