If 20 lb of saturated refrigerant is present, how does its pressure compare to 5 lb of saturated refrigerant at the same temperature?

The correct answer is that the pressure of the saturated refrigerant, regardless of whether it is 20 lb or 5 lb at the same temperature, is the same. This is based on the principles of thermodynamics concerning saturated substances.

In a saturated state, the refrigerant has reached the temperature and pressure at which it can coexist in both liquid and vapor forms. For a specific refrigerant at a given temperature, the saturation pressure is solely determined by that temperature, not by the mass of the refrigerant present. Therefore, whether there are 20 lb or 5 lb, as long as both are at the same temperature and the refrigerant remains saturated, the pressure will remain constant.

Options that suggest a greater or lesser pressure imply a misunderstanding of how saturation works. The last option, which considers the refrigerant type, can be misleading because the saturation pressure for any given refrigerant at a specific temperature remains consistent regardless of the amount present.