For which of the following reactions, $$\Delta $$H is equal to $$\Delta $$U?

An ideal gas undergoes a cyclic process as shown in Figure.


$$\Delta $$U_BC = $$-$$5 kJ mol^-1, q_AB = $$2$$ kJ mol^-1, W_AB = $$-$$5 kJ mol^-1, W_CA = 3 kJ mol^-1. Heat absorbed by the system during process $$CA$$ is :

An ideal gas undergoes isothermal expansion at constant pressure. During the process :

A gas undergoes change from state A to state B. In this process, the heat absorbed and work done by the gas is 5 J and 8 J, respectively. Now gas is brought back to A by another process during which 3 J of heat is evolved. In this reverse process of B to A :