CFCs Destroy Ozone
Chlorine radicals break down the ozone layer
What this lesson covers
Why it matters
A single chlorine atom acts like a tiny wrecking ball, smashing through the ozone shield one molecule at a time.
The idea in plain words
Verify the stoichiometry: one Cl and one O₃ yield one ClO and one O₂.
Predict first
What happens when a chlorine atom collides with an ozone molecule?
Chlorine is highly reactive; it rips an oxygen atom from ozone, creating chlorine monoxide (ClO) and leaving behind ordinary oxygen (O₂).
- They bond permanently to form a stable ClO₃ compound.
- Chlorine steals an oxygen atom, forming ClO and releasing O₂. — correct
- The ozone molecule splits into three oxygen atoms, ignoring the chlorine.
- Chlorine is too heavy to react with light ozone gas.
What you do
Arrange the steps of the chlorine wrecking-ball cycle. Notice the chlorine atom comes out untouched at the end — ready to destroy again. That's why one Cl can wreck ~100,000 ozone molecules.
Check yourself
Why is a single chlorine atom so dangerous to the ozone layer?
The Cl atom is regenerated in subsequent steps, allowing it to destroy ~100,000 ozone molecules.
Identify the correct chemical equation for this step.
The reaction data confirms: Cl + O₃ → ClO + O₂.
What type of reaction is Cl + O₃ → ClO + O₂?
Oxygen is transferred from ozone to chlorine (Cl gains O to become ClO), so it is a redox change.
- It destroys only one ozone molecule before becoming inert.
- It acts as a catalyst, destroying ~100,000 ozone molecules. — correct
- It blocks sunlight, causing ozone to freeze.
- Cl + O₃ → ClO + O₂ — correct
- Cl₂ + O₃ → 2ClO + O₂
- Cl + O₂ → ClO + O
- ClO + O₃ → Cl + 2O₂
- Redox — correct
- Neutralization
- Precipitation
- Combustion