Question

If air contains 78% Nitrogen by volume, what is the solubility of nitrogen in water at 25 degree celisus​

Answer 1

The solubility of nitrogen in water at 25 °C= 4.88 x 10⁻⁴ mol/L

Further explanation

Given

78% Nitrogen by volume

Required

The solubility of nitrogen in water

Solution

Henry's Law states that the solubility of a gas is proportional to its partial pressure  

Can be formulated  

S = kH. P.  

S = gas solubility, mol / L  

kH = Henry constant, mol / L.atm  

P = partial gas pressure  

In the standard 25 C state, the air pressure is considered to be 1 atm, so the partial pressure of N₂ -nitrogen becomes:

Vn / Vtot = Pn / Ptot

78/100 = Pn / 1

Pn = 0.78 atm

Henry constant for N₂ at 25 °c = 1600 atm/mol.L=6.25.10⁻⁴ mol/L.atm

The solubility :

$\tt S=6.25.10^{-4}\times 0.78\\\\S=4.88\times 10^{-4}~mol/L$