Which of the following is an endothermic process?

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

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, meaning heat energy is taken in during the change.
2. Analyze each option by considering whether heat is absorbed or released: for example, neutralization reactions and combustion typically release heat, making them exothermic.
3. Consider phase changes: melting (solid to liquid) requires energy input to overcome intermolecular forces, so it absorbs heat and is endothermic.
4. Condensation (gas to liquid) releases heat as molecules lose energy and come closer together, so it is exothermic.
5. Conclude that among the given options, melting of ice is the endothermic process because it requires heat absorption to change from solid to liquid.