Q. Equal masses of methane and oxygen are mixed in an empty container at $25℃.$ The fraction of the total pressure exerted by oxygen is
A) $\frac{2}{3}$
B) $\frac{1}{3} \times \frac{273}{298}$
C) $\frac{1}{3}$
D) $\frac{1}{2}$
Explanation
(c)
Suppose the equal mass of methane and oxygen = w= 1g
Mole fraction of oxygen = $\frac{w/32}{\frac{w}{32} + w/16}$
=$\frac{\frac{1}{32}}{\frac{3}{32}} = \frac{1}{3}$
Let the total pressure = p
Pressure exerted by oxygen (partial pressure)
= $X_{o_{2}} \times p_{total} = p \times \frac{1}{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.