Question

“The amount of air dissolved in a fluid is proportional to the pressure in the system”, which law is applicable to this statement?

(a) Raoult’s law

(b) Fick’s law

(c) Henry’s law

(d) Newton’s law

I got this question by my school teacher while I was bunking the class.

My query is from Estimating Oxygen Solubility in section Mass Transfer of Bioprocess Engineering

Answer 1

Right answer is (c) Henry’s law

To explain: Solubility of air in water follows Henry’s Law – “the amount of air dissolved in a fluid is proportional to the pressure in the system” – and can be expressed as:

c = pg / kH

where, c = solubility of dissolved gas

kH = proportionality constant depending on the nature of the gas and the solvent

pg = partial pressure of gas (Pa, psi)

The solubility of oxygen in water is higher than the solubility of nitrogen. Air dissolved in water contains approximately 35.6% oxygen compared to 21% in air.