Final answer:
Manganese dioxide acts as a catalyst in the decomposition of potassium chlorate into potassium chloride and oxygen gas, speeding up the reaction without being consumed by it.
Step-by-step explanation:
When heat is added to potassium chlorate, it undergoes a decomposition reaction. In the presence of manganese dioxide as a catalyst, this reaction is significantly accelerated. The role of manganese dioxide is to lower the activation energy necessary for the reaction, allowing it to proceed faster without being consumed or altered in the process. The chemical equation for this reaction, with manganese dioxide as the catalyst, is as follows:
- MnO₂ (s) [Catalyst]
- 2KClO₃ (s) → 2KCl (s) + 3O₂ (g)
The manganese dioxide is typically indicated above the reaction arrow to signify its role as a catalyst. It's important to note that in this decomposition reaction, potassium chlorate breaks down into potassium chloride and oxygen gas.
A specific example of the oxidation state of manganese can be seen in potassium permanganate (KMnO₄), where manganese has an oxidation number of +7. This is a separate context from the reaction described, but illustrates the versatility of manganese compounds in redox reactions.