The pressure of a real gas is less than the pressure of an ideal gas because of .....

The Van der Waals constants '$a$' and '$b$' are related to which of the following respectively?

The inversion temperature $T_i \, (K)$ of hydrogen is (given van der Waal's constants $a$ and $b$ are $0.244 \, atm \, L^2 \, mol^{-2}$ and $0.027 \, L \, mol^{-1}$ respectively).

What are the ideal pressure and volume of a real gas?

What is the volume of $1 \ mole$ of a real gas at $STP$ $(V_{ideal} = 22.4 \ dm^3)$,if the compressibility factor of the real gas is $1.1$ at $STP$ (in $dm^3$)?

Statement $-1$: The compressibility factor at the critical point is the same for different gases following van der Waal's equation.
Statement $-2$: The compressibility factor is independent of pressure at the critical temperature.