If released in a confined space, a liquefied gas may expand to fill the space.

• A. Expand to fill the space
• B. Vaporize completely
• C. Condense rapidly
• D. Decrease in volume

Answer: (A)

Liquefied gases release into a confined space rapidly undergo a flash to vapor and expand far more than their liquid volume, so they quickly fill the available space. This dramatic expansion pushes out and can displace the surrounding air, creating an oxygen-deficient environment and, if the gas is flammable, a dangerous vapor cloud. That’s why the description that best fits is expansion to fill the space. The other ideas don’t describe what typically happens: the gas is not required to vaporize completely to fill the room, it does not condense into a liquid in this scenario, and it does not decrease in volume.