What occurs in an LP tank when gas is drawn off?

When gas is drawn off from a liquid propane (LP) tank, the liquid propane inside the tank undergoes a phase change. As gas is extracted, the remaining liquid propane boils off to replace the gas that has been used. This boiling process occurs because the decrease in pressure caused by drawing off the gas allows more propane molecules to transition from their liquid state to a gaseous state.

This interaction between liquid and gas is critical for maintaining a steady flow of propane gas from the tank. The boiling of the liquid does not freeze the liquid or change the pressure in a way that leads to condensation; rather, it efficiently provides the gas needed for combustion or heating applications. Therefore, the correct answer reflects the fundamental thermodynamic properties of propane and its behavior in response to changes in pressure and heat.