Given :
Henry’s law constant = KH
= 1.25 x 10-3 mol dm-3 atm-1
Pressure of the gas = P = 2.5 atm
Solubility of the gas = S = ?
By Henry’s law,
S = KH × P
= 1.25 × 10-3 mol dm-3 atm-1 x 2.5 atm
= 3.125 × 10-3 mol dm-3
∴ Solubility of gas = 3.125 × 10-3 mol dm-3