In water, which of the following gases has the highest Henry's law constant at 293 K?

Question

Question

This question was previously asked in

AIIMS BSc NURSING 2024 Memory-Based Paper

Answer 1

CONCEPT:

Henry's Law Constant

Henry's Law states that the amount of gas dissolved in a liquid is directly proportional to the partial pressure of the gas above the liquid.
The constant of proportionality is known as Henry's Law Constant (K_H).
A higher Henry's Law constant indicates that the gas is less soluble in water.
Mathematically, Henry's Law is represented as:
C = K_H * P
where,
- C is the concentration of the gas in the liquid.
- K_H is the Henry's Law constant.
- P is the partial pressure of the gas.

EXPLANATION:

The gases mentioned in the options (N₂, O₂, He, H₂) have different solubilities in water at 293 K.
Among these gases, helium (He) has the highest Henry's Law constant.
This means that helium is the least soluble gas in water at 293 K.
The values of the Henry's Law constants are typically as follows:
- N₂: 1.67 × 10^-5 mol/(L·atm)
- O₂: 1.30 × 10^-5 mol/(L·atm)
- He: 3.72 × 10^-4 mol/(L·atm)
- H₂: 7.80 × 10^-5 mol/(L·atm)
As seen, helium (He) has the highest Henry's Law constant, making it the correct answer.

Therefore, in water, helium (He) has the highest Henry's Law constant at 293 K.