Gas hydrates consist of frozen water that encloses gas molecules. What term is used for those gas molecules when trapped?

• A. Clathrates
• B. Gases
• C. Hydrates
• D. Adsorbates

Answer: (A)

Gas hydrates form when water molecules create a rigid, cage-like lattice that traps gas molecules inside. The trapped gas inside these cages is described as a clathrate, and the whole solid is called a clathrate hydrate. This naming highlights the enclosure of the gas by the water framework. For example, methane clathrates are common natural hydrates where methane is the guest molecule within the water lattice. Other terms don’t fit because a simple gas is not encapsulated, a hydrate refers to the entire solid compound, and adsorption describes molecules sticking to a surface rather than being encapsulated in a cage.