If $O_2$ gas is bubbled through water at 303 K, the number of millimoles of  $O_2$ gas that dissolve in 1 litre of water is __________(Nearest Integer)

(Given: Henry’s law constant for $O_2$ at 303 K is 46.82 k bar and partial pressure of  $O_2=0.920bar)$ (Nearly negligible)

Complete Solution:

Using Henry's Law:

x = p / K_H

where:

• p = 0.920 bar,
• K_H = 46.82 × 10³ bar.

x = 0.920 / (46.82 × 10³) = 1.965 × 10^-5.

Number of moles of water in 1 liter (assuming density = 1 g/mL):

Moles of water = 1000 g / 18 g/mol = 55.56 mol.

Moles of O₂ = x × 55.56 = 1.965 × 10^-5 × 55.56 = 1.09 × 10^-3 mol.

1.09 × 10^-3 mol × 1000 = 1.09 mmol.

Final Answer

1 mmol