Question
Chemistry Question on Solutions
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
1 bar
B
0.5 bar
C
1.5 bar
D
2.0 bar
Answer
0.5 bar
Explanation
Solution
From Henry's law,we know P = k × C
Given:
Henry's law constant (k) = 6.85 x 10-4 mol.dm-3.bar-1
Concentration (C) = 6.85 x 10-4 mol.dm-3
Substituting
P = 6.85 x 10-4 mol.dm-3.bar-1 × 6.85 x 10-4 mol.dm-3
P = 4.69725 x 10-7 bar,which is approximately 0.5 bar