Answer:
Solubility of N₂ in water exposed to air at 25°C is 6.09x10⁻⁴ mol/L
Explanation:
Henry's law → C = K . Partial pressure of gas
where C is solubility
and K is Henry's law constant for nitrogen in water
First of all, let's find out the partial pressure for N₂.
We have the mole fraction so
Mole fraction N₂ = Partial pressure N₂ / Total pressure
0.78 = Partial pressure N₂ / 1.28 atm
0.78 . 1.28 atm = Partial pressure N₂ → 0.9984 atm
C = 6.1x10⁻⁴ M /atm . 0.9984 atm
C = 6.09x10⁻⁴ mol/L