Which element present in a CFC or HCFC molecule is primarily responsible for ozone depletion in the stratosphere?

• A. Hydrogen
• B. Fluorine
• C. Chlorine
• D. Carbon

Answer: (C)

Verified step by step guidance

1. Understand that CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) are compounds containing carbon, fluorine, chlorine, and sometimes hydrogen atoms.
2. Recall that ozone depletion in the stratosphere is caused by the catalytic destruction of ozone molecules (O₃) by certain atoms released from these compounds under UV radiation.
3. Identify which element in these molecules can break free as an atom and catalyze the breakdown of ozone. This element must be able to react with ozone and regenerate to continue the cycle.
4. Recognize that chlorine atoms (Cl) released from CFCs and HCFCs are highly reactive with ozone, initiating a chain reaction that destroys ozone molecules.
5. Conclude that among the elements listed (hydrogen, fluorine, chlorine, carbon), chlorine is primarily responsible for ozone depletion due to its ability to catalytically destroy ozone in the stratosphere.