Question
20.0 dm ^ 3 of an ideal gas ' X ' at 600 K and 0.5 MPa undergoes isothermal reversible expansion until pressure of the gas is 0.2 MPa. Which of the following option is correct? (Given: 2=0.3010 and 5=0.6989)
JEE Main
Chemistry
Thermodynamics (C)
2026
JEE Main 2026 (28 January Shift 1)
JEE Main Chemistry Question (2026) — Solution
Options
- A. w =-9.1 ~kJ , U =0, H =0, q =9.1 ~kJ
- B. w =+4.1 ~kJ , U =0, H =0 ; q =-4.1 ~kJ
- C. w =9.1 ~J , U =9.1 ~J , H =0 ; q =0
- D. w =-3.9 ~kJ , U =0, H =0 ; q =3.9 ~kJ
Answer
A. w =-9.1 ~kJ , U =0, H =0, q =9.1 ~kJ
Step-by-step solution
For isothermal reversible process U = H = 0 w_ iso = -p_1 v_1 P_1 P_2 w_ iso = -0.5 10^6 20 10^ -3 0.5 0.2 w_ iso = -0.5 10^6 20 10^ -3 2.303 (.6989 - .3010) w -9.1 kJ q = -w = 9.1 kJ
Related: Chemistry — Thermodynamics (C) · All PYQ Banks