Q. Pressure exerted by 1 mole of methane in a 0.25 L container at 300 K using van der Waals’ equation is $\left( Given,\ a = 2.253\ atm\ L^{2}\ mol^{- 2},\ b = 0.0428\ L\ {mol}^{- 1} \right)$

A) 82.82 atm
B) 152.51 atm
C) 190.52 atm
D) 70.52 atm
Explanation

(a)
From van der Waals’ equation,
$\left( p + \frac{n^{2}a}{V^{2}} \right)\ (V - nb) = RT$
$\left( p + \frac{2.253}{0.25 \times 0.25} \right)(0.25 - 0.0428)$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = 0.0821 \times 300$
$\ (p + 36.048)(0.2072) = 24.63$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ p + 36.048 = 118.87\$
$p = 118.87 - 36.048 = 82.82\ atm$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.