Question

Henry’s law constant for solubility of methane in benzene is 4.2 × 10^-5 mm Hg at a particular constant temperature. At this temperature calculate the solubility of methane at

1. 750 mm Hg
2. 840 mm Hg.

Answer 1

`("K"_"H")_"benzene"` = 4.2 × 10^-5 mm

Solubility of methane = ?

P = 750 mm Hg P = 840 mm Hg

According to Henrys Law,

P = K_H `"X"_"in solution"`

750 mm Hg = 4.2 × 10^-5 mm Hg. `"X"_"in solution"`

⇒ `"X"_"in solution" = 750/(4.2 xx 10^-5)`

i. e solubility = 178. 5 × 10⁵

similarly at P = 840 mm Hg

solubility = `840/(4.2 xx 10^-5) = 200 xx 10^-5`