Question

a single compound breaks down into two or more simpler products; ab = a + b
combustion reaction
combustible
combination (synthesis)
decomposition reaction

Explanation:

To solve this, we analyze each option:

• Combustion reaction: Involves reacting with oxygen to produce oxides, not breaking down a compound.
• Combustible: Refers to a substance's ability to burn, not a reaction type.
• Combination (synthesis): Involves combining substances to form a more complex compound (A + B → AB), opposite of the given reaction.
• Decomposition reaction: Defined as a compound breaking down into simpler substances (AB → A + B), matching the description.

Answer:

D. decomposition reaction