The Partial Pressure of Helium in a Gaseous Mixture of Helium

Multiple Choice

The partial pressure of helium in a gaseous mixture of helium and nitrogen trifluoride is

A) the pressure that the helium would exert in the absence of the nitrogen trifluoride
B) the percentage of the total pressure of the mixture that is contributed by helium
C) equal to the total pressure divided by helium's molar mass
D) equal to the total pressure divided by the number of helium atoms present