35 moles of nitrogen gas is mixed with 25 moles of oxygen ga

3.5 moles of nitrogen gas is mixed with 2.5 moles of oxygen gas in a 1.00 L container at STP. What is the mole fraction of the oxygen gas?

A. .42

B. .58

C. .71

D. 1.0

E1.4

Solution

its definitely option A

ie mole fraction of O2 = moles of o2/(total no. of moles)

mole fraction of O2   = 2.5/6

                                        = 0.41666 ~ 0.42

which is option A