Which of the following is true about HFCs compared to many CFCs?

• A. HFCs typically have zero ODP, unlike many CFCs.
• B. HFCs are always flammable.
• C. HFCs are more toxic.
• D. HFCs cannot be used in refrigeration systems.

Answer: (A)

Ozone depletion potential is what this question hinges on. CFCs contain chlorine, and when they're broken down in the upper atmosphere, chlorine catalytically destroys ozone molecules. HFCs replace the chlorine with hydrogen and fluorine, so they don’t release chlorine to drive ozone loss. That means HFCs have essentially zero ozone depletion potential, whereas many CFCs have a positive ODP.

Other points to keep in mind: HFCs are not inherently flammable, and they are widely used in refrigeration systems as replacements for CFCs. They can have high global warming potential, which is a separate environmental concern, but that doesn’t change their ozone depletion status.

So the true statement is that HFCs typically have zero ODP, unlike many CFCs.