Question

Choose the correct statement

• A. K_H value is same for a gas in any solvent
• B. Higher the K_H value more the solubility of gas
• C. K_H value increases on increasing the temperature of the solution
• D. Easily liquefiable gases usually has lesser K_H values

Answer 1

The Correct Option is C

Let's evaluate each statement:

1. \(K_H\) value is same for a gas in any solvent: This is incorrect. The Henry's law constant \(K_H\) varies with the type of solvent. It is specific to the gas-solvent combination.

2. Higher the \(K_H\) value, more the solubility of gas: This is incorrect. According to Henry's law, a higher \( K_H \) value corresponds to a lower solubility of the gas. The solubility of a gas in a solvent is inversely proportional to \( K_H \).

3. K_H value increases on increasing the temperature of the solution: This is correct. As the temperature increases, the solubility of gases generally decreases, which causes the Henry's law constant \( K_H \) to increase. This is because gases become less soluble at higher temperatures.

4. Easily liquefiable gases usually have lesser K_H values: This is incorrect. Gases that are easily liquefiable, such as ammonia, generally have higher solubility in a solvent, which corresponds to a lower \( K_H \) value.

Therefore, the correct answer is (C): \( K_H \) value increases on increasing the temperature of the solution.

Answer 2

1. Recall Henry's Law
Henry's Law states that the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid. Mathematically, it's often expressed as:

$p = K_H c$

where:
- $p$ is the partial pressure of the solute gas above the solution
- $c$ is the concentration of the solute gas in the solution (typically in molarity)
- $K_H$ is the Henry's Law constant, which has units dependent on how concentration 'c' is expressed (e.g., pressure/concentration).

2. Analyze the statements based on Henry's Law

(A) $K_H$ value is same for a gas in any solvent: This is incorrect. The Henry's Law constant, $K_H$, depends on the gas, the solvent, and the temperature. Different solvents will have different affinities for the gas, leading to different $K_H$ values.

(B) Higher the $K_H$ value more the solubility of gas: This is incorrect. From the formula $p = K_H c$, we can rearrange it to solve for concentration: $c = \frac{p}{K_H}$. This shows that the concentration of the gas in the solution (solubility) is inversely proportional to the Henry's Law constant $K_H$. Therefore, a *higher* $K_H$ value implies *lower* solubility.

(C) $K_H$ value increases on increasing the temperature of the solution: This is correct. The solubility of most gases in liquids decreases as temperature increases. Since $c = \frac{p}{K_H}$, if solubility ($c$) decreases with increasing temperature, and pressure ($p$) remains constant, then $K_H$ must increase.

(D) Easily liquefiable gases usually has lesser $K_H$ values: This is correct. Easily liquefiable gases have strong intermolecular forces. These forces also favor their dissolution in a solvent, leading to higher solubility. Since higher solubility means lower $K_H$ value, this statement is correct.

Based on the analysis, statement (C) is the most directly related to Henry's Law and gas solubility.

Final Answer:
(C) $K_H$ value increases on increasing the temperature of the solution