Identify which equation represents a decomposition reaction.

Identify which equation represents a decomposition reaction.

• A. A + B → AB
• B. AB → A + B
• C. CH4 + 2 O2 → CO2 + 2 H2O
• D. NaCl + AgNO3 → NaNO3 + AgCl

Answer: (B)

Decomposition reactions involve a single compound breaking into two or more simpler substances. In AB → A + B, the single compound AB splits into two products, A and B, which is exactly what decomposition looks like. The other equations illustrate different types of reactions: A + B → AB is synthesis, where two substances combine to form one compound. CH4 + 2 O2 → CO2 + 2 H2O is combustion, a hydrocarbon reacting with oxygen to produce carbon dioxide and water. NaCl + AgNO3 → NaNO3 + AgCl is a metathesis (double displacement) reaction that forms new compounds.

Decomposition reactions involve a single compound breaking into two or more simpler substances. In AB → A + B, the single compound AB splits into two products, A and B, which is exactly what decomposition looks like.

The other equations illustrate different types of reactions: A + B → AB is synthesis, where two substances combine to form one compound. CH4 + 2 O2 → CO2 + 2 H2O is combustion, a hydrocarbon reacting with oxygen to produce carbon dioxide and water. NaCl + AgNO3 → NaNO3 + AgCl is a metathesis (double displacement) reaction that forms new compounds.