For real gases (van der waals ' gas )

For a real gas (van der Waal's gas)

Why do real gases deviate from ideal behaviour ? Write the equation of state for real gases (van der Waals equation).

For a real gas, the van der Waals constant 'a' is zero. Can the gas the liquefied? Explain.

A real gas follows van der waals equation. Find the compressibility for 1 mol of the gas at its critical temperature.

Compressibility factor (Z) for a van der Waals real gas at critical point is

Using van der waals equation, explain why real gases behave like an ideal gas at very low pressures and high temperature.