Value of Henry's constant KH

Options

A. increases with increase in temperature.
B. decreases with increase in temperature.
C. remains constant.
D. first increases then decreases

Answer

To determine how Henry's constant (KH) is dependent on temperature, we can follow these steps:

### Step 1: Understand Henry's Law
Henry's Law states that the partial pressure (P) of a gas above a liquid is directly proportional to the mole fraction (x) of the gas in the liquid. This relationship can be expressed mathematically as:
\[ P = K_H \cdot x \]
where:
- \( P \) is the partial pressure of the gas,
- \( K_H \) is Henry's constant,
- \( x \) is the mole fraction of the gas in the liquid.

### Step 2: Analyze the Effect of Temperature
Experimental data shows that as the temperature increases, the solubility of gases in liquids generally decreases. This means that at higher temperatures, a gas will exert a higher partial pressure for a given mole fraction in the liquid.

### Step 3: Relate Temperature to Henry's Constant
From the relationship given by Henry's Law, if the solubility of a gas decreases with an increase in temperature, this implies that Henry's constant \( K_H \) must increase as temperature increases. Therefore, we can conclude:
- As temperature increases, \( K_H \) increases.

### Step 4: Conclusion
The value of Henry's constant \( K_H \) increases with an increase in temperature. This is a well-established experimental observation.

### Final Answer
The value of Henry's constant \( K_H \) increases with an increase in temperature.

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