A mixture of dihydrogen and dioxygen at one bar pressure contains 20% by weight of dihydrogen . What would be the partial pressure of dihydrogen in bar ?

Explanation

Suppose the total mass of the mixture is 100 g.
`:. " Mass of " H_2 = 20 g, " Mass of " O_2`
`= 100 - 20 = 80 g`
Number of moles of `H_2 = 20/2 = 10`
Number of moles of `O_2 =80/32 =2.5`
Total number of moles in the mixture = `10 + 2.5 = 12.5`
`:. " Partial pressure of " H_2 = ("Moles of " H_2)/(" Total no. of moles")xx " Total pressure "`.
`=10/(12.5)= 0.8` bar