Question

Identify a pair of gases from following that does not obey Henry's law.

• A. \(\text{NH}_3\) and \(\text{CO}_2\)
• B. \(\text{CO}_2\) and \(\text{O}_2\)
• C. \(\text{NH}_3\) and \(\text{N}_2\)
• D. \(\text{N}_2\) and \(\text{CH}_4\)

Hint:

Gases that react with water, such as ammonia and carbon dioxide, do not follow Henry law.

Answer 1

The Correct Option is A

Step 1: Condition for the law.
Henry law is valid for gases that stay as the same molecule in solution, with no chemical reaction with the solvent.

Step 2: Find reactive gases.
$\text{NH}_3 + \text{H}_2\text{O} \rightleftharpoons \text{NH}_4^+ + \text{OH}^-$ and $\text{CO}_2 + \text{H}_2\text{O} \rightleftharpoons \text{H}_2\text{CO}_3$.

Step 3: Select the pair.
Only option (A) has both gases of this type. All other options pair a reactive gas with a non-reactive one, or two non-reactive gases.

Final Answer:
Option (A) is correct. \[ \boxed{\text{(A)}} \]