Q. A and B ideal gases. The molecular weights of A and B are in the ratio of 1:4. The pressure of a gas mixture containing equal weight of A and B is p atm. What is the partial pressure (in atm) of B in the mixture?
A) $\frac{P}{5}$
B) $\frac{P}{2}$
C) $\frac{P}{2.5}$
D) $\frac{3P}{4}$
Explanation
(a)
Mol wt. ratio of A and B =1:4
$\therefore$ Mole ratio of A and B, if equal weight of A and B are taken = 4:1
$\therefore$ Partial pressure of B = $\frac{1}{(1 + 4)} \times p$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \frac{p}{5}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.