Question

The solubility of CO2 in water at 25C and partial pressure=1 atm is 0.034M. How high do you have to increase the carbon dioxide pressure to get a CO2 of 0.15M, assuming that CO2 continues to obey Henry's law?

Answer 1

According to Henry's law , H = c / P

Where

H = Henry's constant

c = concentration of the solution

P = pressure

Since the solution is same so H is constant thereby c is proportional to P

c / c' = P / P'

Where

c = initial concentration = 0.034 M

c' = final concentration = 0.15 M

P = initial pressure = 1 atm

P' = final pressure = ?

Plug the values we get

P' = ( c'xP) / c

   = ( 0.15x1) / 0.034

   = 4.412 atm

Therefore the pressure we have to increase is 4.412 atm