Q. When two moles of hydrogen expands isothermally against a constant pressure of 1 atm, at 25$℃$ from 15 L to 50 L, the work done (in litre atm) will be
A) 17.5
B) 35
C) 51.5
D) 70
Explanation
(b)
p=1 atm
$\mathrm{\Delta}V = (50 - 15) = 35\ L$
$\therefore$ $W = - p.\mathrm{\Delta}V = - 1 \times 35$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = - 35\$Latm
Hence, work done by the system on the surroundings is equal to 35 L-atm.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.