Partial pressure of `N_(2)` gas at 298 K is 0.987 bar If is bubbled through water at 298 K, how many millimoles of `N_(2)` gas would be dissolved in 1 litre of water ? (Given : `K_(H)` for `N_(2)` at 298 K =76.48 bar).

Options

A. 0.85
B. 0.693
C. 0.981
D. 0.453

Answer

B

Explanation

A/c to Henry's law
`pN_(2) = K_(H) xx N_(2)`
or `xN_(2)=(pN_(2))/K_(H)=(0.96 "bar")/(76800 "bar")=1.25 xx 10^(-5)`
if n moles of `N_(2)` are present in 1 L of water (55.5 moles)
`xN_(2)=n/(n+55.5)=n/55.5`
or `n = xN_(2) xx 55.5 = 1.25 xx 10^(-5) xx 55.5 "moles"`
`= 69.3 xx 10^(-5)` Moles =0.693 millimoles