Question

Which thermodynamic parameter is not a state function?

(a) q at constant pressure

(b) q at constant volume

(c) W at adiabatic

(d) W at isothermal

Answer 1

Correct option  (d) W at isothermal

Explanation:

H and U are state functions but W and q are not state functions.

From the equation, ΔH = ΔU + ΔPV

At constant pressure, ΔH = ΔU + PΔV

At constant volume, ΔH = ΔU + VΔP

At constant pressure, ΔP = 0, ΔH = q_p

so, it is a state function.

At constant volume, ΔV = 0, ΔU = q_v

so, it is a slate function.

Work done in any adiabatic process is state function.

Work done in isothermal process is not a state function.