Final answer:
R-134a (HFC-134a) is the strong candidate for replacing CFC (R-12) as it does not deplete the ozone layer and is widely accepted in refrigeration systems. While HCFCs like R-22 and R-123 are interim replacements, they are eventually being phased out due to their environmental impact.
Step-by-step explanation:
The successor to Freon-12, a chlorofluorocarbon (CFC) also known as CCl₂F₂ or R-12, is a significant concern due to R-12's ozone-depleting potential. Seeking a replacement, options include hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) which have less environmental impact. Out of the choices provided, R-134a, also known as HFC-134a or CF₃-CH₂F, stands out. R-134a does not deplete the ozone layer and has become a widely accepted substitute for R-12 in refrigeration systems.
Other compounds such as carbon tetrachloride and methyl chloroform are being phased out due to their toxicity and environmental risks. Instead, safer alternatives like dichloromethane are being used. HCFCs like HCFC-22 (hydrochlorofluorocarbon-22), HCFC-123 (hydrochlorofluorocarbon-123), and HCFC-124 (hydrochlorofluorocarbon-124) have also been considered as transitional refrigerants, as they cause less ozone depletion compared to CFCs.
It is important to note that R-22, an HCFC, is also not an ideal long-term replacement due to its ozone-depleting potential and is being phased out under international agreements. R-123, another HCFC, is less damaging but still not preferable compared to HFCs. HCFC-124 and HCFC-141b can be seen as interim substitutes but are also part of a phase-out process to reduce ozone depletion and global warming potential.