Final answer:
The reaction 2KClO₃(s) → 2KCl(s) + 3O₂(g) is a decomposition reaction, where potassium chlorate breaks down into potassium chloride and oxygen gas when heated.
Step-by-step explanation:
The reaction 2KClO₃(s) → 2KCl(s) + 3O₂(g) is classified as a decomposition reaction. This is because a single compound, potassium chlorate (KClO₃), breaks down into two simpler substances, potassium chloride (KCl) and oxygen gas (O₂) when heated. Decomposition reactions are the opposite of synthesis reactions, where two or more reactants combine to form a single product. An example of a synthesis reaction is when sodium metal reacts with chlorine gas to form sodium chloride (NaCl). In contrast, the oxidation-reduction reaction involves the transfer of electrons between substances, such as in the reaction 2K(s) + Br₂(l) → 2KBr(s), where potassium loses electrons and bromine gains them. The reaction given in the student's question does not involve a transfer of electrons but the breakdown of a compound, thus confirming its classification as a decomposition reaction.