During combustion of hydrocarbons with plenty of oxygen, which is produced?

• A. Carbon dioxide
• B. Water
• C. Energy
• D. Salt

Answer: (C)

Combustion of hydrocarbons with plenty of oxygen is exothermic, meaning the reaction releases energy as heat (and often light). In complete combustion, the hydrocarbon reacts with oxygen to form carbon dioxide and water, which are produced as chemical outputs. However, the energy released during bond breaking and new bond formation is the key idea here—the reaction gives off energy that we can feel as heat. Salt is not formed in this process, so the energy released is the most appropriate answer among the options.