
Answer:
A 52.63%
Explanation:
The mole fraction of each gas  is equivalent to the ratio of the partial pressure as indicated below:
Partial pressure of Hydrogen = 5.00
Partial pressure of Carbon-dioxide= Â 4.50
Total gas pressure = 9.50
Mole fraction of Hydrogen = Partial pressure of Hydrogen/ Total gas pressure
                      =   5.00/9.50
                      =  0.5263
                      = 52.63%