Final answer:
Equation A represents a synthesis reaction, where hydrogen and chlorine gases combine to form hydrogen chloride. Equation B represents a combustion reaction, wherein methane combines with oxygen to produce carbon dioxide and water.
Step-by-step explanation:
Equation A: H2 + Cl2 → 2HCl represents a synthesis reaction, where two or more reactants combine to form a single product. In this case, hydrogen gas and chlorine gas react to form hydrogen chloride.
Equation B: CH4 + 2O2 → CO2 + 2H2O represents a combustion reaction, which is a specific type of synthesis reaction where a substance combines with oxygen, releasing heat and light. Methane reacts with oxygen to produce carbon dioxide and water.
Therefore, the correct answers are: Equation A represents a synthesis reaction, and Equation B represents a combustion reaction.