Which of the following is an endothermic process?

• A. Combustion of methane
• B. Neutralization of hydrochloric acid with sodium hydroxide
• C. Melting of ice
• D. Condensation of water vapor

Answer: (C)

Verified step by step guidance

1. Understand the definition of an endothermic process: it is a process that absorbs heat from the surroundings, resulting in a positive heat flow into the system.
2. Analyze each option by considering whether heat is absorbed or released during the process:
3. 1. Combustion of methane is a chemical reaction that releases heat, so it is exothermic.
4. 2. Neutralization of hydrochloric acid with sodium hydroxide is also an exothermic reaction because it releases heat when an acid and base react.
5. 3. Melting of ice involves changing solid water to liquid water, which requires heat absorption to break the hydrogen bonds, making it an endothermic process.
6. 4. Condensation of water vapor releases heat as vapor changes to liquid, so it is exothermic.