Question

Which of the following gases causes depletion in ozone layer?

• A. He
• B. NO
• C. \(\mathrm{CO}_{2}\)
• D. \(\mathrm{H}_{2}\)

Hint:

Oxides of nitrogen react with ozone in the stratosphere and destroy it.

Answer 1

The Correct Option is B

Step 1: Elimination
Helium is inert and does not react with ozone.
$\text{CO}_2$ causes global warming, not ozone depletion.

Step 2: Check hydrogen
$\text{H}_2$ is not present in significant amounts in the stratosphere and is not an ozone depleter.

Step 3: Result
NO reacts with $\text{O}_3$ in a catalytic cycle and therefore depletes the layer.

Final Answer:
NO is the ozone-depleting gas among the options. \[ \boxed{\text{(B) }\text{NO}} \]