Azeotropes are numbered in which range?

Azeotropes are mixtures of two or more substances that maintain a constant boiling point and composition during distillation, which makes them unique in how they behave during phase changes. The correct range for the identification of refrigerant azeotropes falls within the range of 500-599. This numbering system is primarily used in the context of refrigerants and their classifications, and the designation helps technicians and professionals identify specific refrigerants that may behave as azeotropes.

Refrigerant blends can exist as azeotropes, meaning they do not separate into their individual components upon boiling. This is a critical factor for technicians to understand in order to appropriately handle and charge refrigerants in HVAC systems. The other specified ranges are used for different refrigerant classifications or groups and do not pertain to azeotropes, thereby making the range 500-599 the correct choice for this context.