In the process `AtoBtoC`, the change in internal energy of the system in the steps `AtoB and B to C ` are -x `jK*mol^(-1)` and `ykJ*mol^(-1)`, respectively. What will be the change in internal energy of the system in the step `C toA`?

Explanation

`AtoBtoC`
Given, `DeltaU_(AtoB)=-xkJ*mol^(-1) and DeltaU_(BtoC)=ykJ*mol^(-1)`
`therefore DeltaU_(CtoA)=-DeltaU_(AtoC)=(x-y)kJ*mol^(-1)` [since U is a state function,, its change in the forward direction of a process is the same as that in the backward direction but opposite in sign.].