A mixture of dihydrogen and dioxygen at one bar pressure contains 20% by weight of dihydrogen. Calculate the partial pressure of dioxygen.

Options

A. 0.8 bar
B. 0.6 bar
C. 0.4 bar
D. 0.2 bar

Answer

D

Explanation

20g of dihydrogen present in 100 g mixture , thus moles of dihydrogen `=(20)/(2) = 10` mol
Mole of oxygen `=((100-20)g)/(32g) = (80)/(32) = (5)/(2) "mol"`
Mole freaction of oxygen `=((5)/2)/(10 + (5)/(2)) = (5)/(25) = 1/5`
Partial pressure of oxygen = Mole fraction ` xx ` total pressure
` = (1)/(5) xx 1 = 0.2` bar