The relation $\Delta H = \Delta U + P \Delta V$ is valid for a system under which of the following conditions?

$5 \ mol$ of an ideal monoatomic gas is compressed isothermally from $(40 \ L, 5 \ bar)$ to $4 \ L$. The magnitude of maximum work done on the gas in this compression is

Which of the following compounds is $NOT$ present in its standard state at $25^{\circ} C$ and $1 \text{ atmosphere}$ pressure?

Assertion : During an adiabatic process,heat energy is not exchanged between the system and its surroundings.
Reason : The temperature of a gas increases when it undergoes an adiabatic expansion.

Which of the following is not a state function?

The internal energy change when a system goes from state $A$ to $B$ is $40 \, kJ/mol$. 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?