Which of the following statements about refrigerants is true?

Refrigerants are substances used in air conditioning and refrigeration systems to transfer heat. The correct statement is that refrigerants cannot be mixed. This is crucial because mixing different types of refrigerants can lead to chemical reactions that may produce harmful byproducts or cause system failures. A system designed for a specific refrigerant has specific operating pressures and temperature ranges, which can be adversely affected by the introduction of an incompatible refrigerant.

When different refrigerants are mixed, the thermodynamic properties, efficiency, and the overall functioning of the refrigeration cycle can be jeopardized, potentially causing significant damage to the system and posing safety risks.

In contrast, the other statements present ideas that do not align with the safe handling and use of refrigerants. Venting refrigerants is not safe or legal under environmental regulations due to their potential ozone-depleting effects and contribution to global warming. Refrigerants can often be reclaimed and reused in different systems, but they must be handled properly. Additionally, refrigerants are not inert and can be harmful to both human health and the environment if not managed correctly.