The internal energy change when a system goes fromk state `A` to `B` is `40 kJ mol^(-1)`. If the system goes from `A` to `B` by a reversible path and returns to state `A` by an irreversible path, what would be the net change in internal energy?

Options

A. `40 kJ`
B. ` gt 40 kJ`
C. ` lt 40 kJ`
D. zero

Answer

D

Explanation

Change in internal energy is a state function
`:. DeltaU(AtoB)=40 kJ mol^(-1)`
`DeltaU(BtoA)=-40 kJ mol^(-1)`
`:. ` Net change in internal energy `=` Zero.