Question

Calculate the pressure of gas if the solubility of gas in water at 25°C is 6.85 x 10^–4 mol.dm^–3. (Henry’s law constant is 6.85 x 10^–4 mol.dm^–3.bar^–1)

• A. 0.5 bar
• B. 1 bar
• C. 1.5 bar
• D. 2.0 bar

Answer 1

The Correct Option is B

Concept Used: Henry’s Law

Henry’s Law relates the solubility of a gas in a liquid to the pressure of the gas above the liquid. It is mathematically represented as:

S = K_H × P

Where:

• S = solubility of gas (mol·dm^–3)
• K_H = Henry’s law constant (mol·dm^–3·bar^–1)
• P = pressure of the gas (bar)

 

Step-by-Step Solution:

Given:

• Solubility, S = 6.85 × 10^–4 mol·dm^–3
• Henry’s Law Constant, K_H = 6.85 × 10^–4 mol·dm^–3·bar^–1

Using Henry’s Law:

S = K_H × P

Rearranging the formula to find pressure (P):

P = S / K_H

Substitute the values:

P = (6.85 × 10^–4) / (6.85 × 10^–4)

P = 1 bar

Final Answer: Option 2: 1 bar