Question

Given below are two statements: Statement–I: $K_H$ is constant with change in concentration of gas till the solution is dilute at a given temperature. Statement–II: According to Henry’s law, the partial pressure of gas in vapour phase is inversely proportional to the mole fraction of gas in solution.

• A. Both Statement–I and Statement–II are correct
• B. Both Statement–I and Statement–II are incorrect
• C. Statement–I is correct, Statement–II is incorrect
• D. Statement–I is incorrect and Statement–II is correct

Hint:

Always remember Henry’s law in the form $p = K_H x$. Any mention of \textbf{inverse proportionality} directly signals an incorrect statement.

Answer 1

The Correct Option is C

The given statements concern Henry's Law, which is a critical principle in physical chemistry regarding gas solubility in liquids.

1. Understanding Henry’s Law: Henry's Law states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid. This relationship is expressed by the formula: P = K_H \cdot X where P is the partial pressure of the gas, K_H is Henry's law constant, and X is the mole fraction of the gas in the solution.
2. Analysis of Statement–I: The first statement says, “K_H is constant with change in concentration of gas till the solution is dilute at a given temperature.” - This is correct because Henry's law constant K_H is a constant for a given gas-solvent combination at a specific temperature and depends on the nature of the gas and solvent, remaining unchanged with concentration variations as long as the solution is dilute.
3. Analysis of Statement–II: The second statement mentions that the partial pressure of gas in the vapor phase is inversely proportional to the mole fraction of gas in the solution. However, as discussed, according to Henry’s Law, the partial pressure is directly proportional to the mole fraction, not inversely. - Therefore, this statement is incorrect.
4. Conclusion: Based on the explanation above: - Statement–I is correct as it aligns with the description of the K_H consistency. - Statement–II is incorrect as it misinterprets Henry's Law by stating an inverse relationship instead of a direct one.

Thus, the correct answer is: Statement–I is correct, Statement–II is incorrect.