H 2 S, a toxic gas with rotten egg like smell, is used for the qualitative analysis. If the solubility of H 2 S in water at STP is 0.195 m, calculate Henry’s law constant.

Question

Philoid · Accepted Answer

According to Henry's law,

'At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.'

Stated as,

p = K_Hx

Where,

P = partial pressure of the solute above the solution

K_H = Henry's constant

x = concentration of the solute in the solution

Given,

Solubility of H₂S in water at STP is 0.195 m

We know,

At STP pressure p = 0.987 bar.

0.195 mol of H₂S is dissolved in 1000g of water

Moles of water =

= 55.56 g/mol

∴ the mole fraction of H₂S =

=

= 0.0035

According to Henry's law,

p = K_Hx

K_H =

K_H = 282 bar

∴ The Henry’s law constant is 282 bar

H2S, a toxic gas with rotten egg like smell, is used for the qualitative analysis. If the solubility of H2S in water at STP is 0.195 m, calculate Henry’s law constant.

H₂S, a toxic gas with rotten egg like smell, is used for the qualitative analysis. If the solubility of H₂S in water at STP is 0.195 m, calculate Henry’s law constant.