Question

H₂S, a toxic gas with rotten egg like smell is used for the qualitative analysis. 1f the solubility of H₂S in water at STP is 0.195 m. Calculate Henrvs law constant.

Answer 1

Solubility of H₂S gas = 0.195 m 

= 0.195 mole in 1 kg of the Solvent (water) 

1 kg of the solvent (water) = 1000 g = \(\frac{1000\,g}{18\,g\,mol^{-1}}\) = 55.55 moles

Mole fraction of H₂S gas in the solution (x) = \(\frac{0.195}{0.195+55.55}\) = 0.0035

Pressure at STP = 0.98 7 bar 

Applying Henry’s law

\(P_{H_2S}=K_H\times x_{H_2S}\)