For isothermal reversible process ΔU=ΔH=0
wiso=−p1v1lnP2P1
wiso=−0.5×106×20×10−3ln0.20.5
wiso=−0.5×106×20×10−3×2.303×(.6989−.3010)
w≃−9.1 kJ
q=−w=9.1 kJ
JEE Main 2026 — Chemistry Physical Chemistry
20.0dm3 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: log2=0.3010 and log5=0.6989)
Held on 28 Jan 2026 · Verified 6 Jul 2026.
w=−9.1 kJ,ΔU=0,ΔH=0,q=9.1 kJ
w=+4.1 kJ,ΔU=0,ΔH=0;q=−4.1 kJ
w=9.1 J,ΔU=9.1 J,ΔH=0;q=0
w=−3.9 kJ,ΔU=0,ΔH=0;q=3.9 kJ
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