Final answer:
Vehicles manufactured in 1993 and older commonly used R-12 (Freon-12) as the refrigerant, which is a chlorofluorocarbon (CFC). This substance would be in a gaseous state at room temperature.
Step-by-step explanation:
The refrigerant used in vehicles manufactured in 1993 and older was typically R-12, also known as Freon-12. This chlorofluorocarbon (CFC) compound was later replaced by R-134a due to environmental concerns, R-22, and other hydrochlorofluorocarbons (HCFCs) like HCFC-123 and HCFC-124 that have less impact on the ozone layer. However, these too are in the process of being phased out for more environmentally friendly alternatives.
In regards to the related exercises, Freon-12, with a boiling point of -29.8°C, would be a gas at room temperature (25°C), as it's well above its boiling point. HCFC-142b is a molecule mentioned as a replacement for CFCs and can be prepared in industrial processes relevant to refrigerants and solvents.