Which thermodynamic parameter is not a state function?

H and U are state functions but W and q are not state function. From the equation, H U PV At constant pressure, H U P V At constant volume, H U V P At constant pressure, y P 0, H q So, it is a state function. At constant volume, V 0, U q, So, it is a state function. Work done in any adiabatic process is state function U q W q 0 U W Work done in isothermal process is not a state function. W q T 0,q 0