Which statement correctly describes Liquefied Gases?

• A. It is partly liquid at temperatures above -50°C
• B. It is always fully liquid at room temperature
• C. It is a gas that has been dissolved in a solvent
• D. It is a gas that remains fully gaseous at -50°C

Answer: (A)

Liquefied gases are gases that have been turned into liquids by cooling or compression and kept under pressure so they stay in liquid form. Because they’re stored as liquids, the container often contains both liquid and vapor. As the temperature rises above about -50°C for many of these substances, part of the liquid will boil off, creating a mixture of liquid and gas rather than a single, pure phase. That is why describing them as partly liquid at temperatures above -50°C best fits their behavior. The other statements don’t fit: they aren’t required to be fully liquid at room temperature (they typically vaporize away), they aren’t simply a gas dissolved in a solvent, and they aren’t necessarily fully gaseous at -50°C since liquid can still be present under pressure.