States Of Matter

Which among the following statements is/are
incorrect regarding real gases?

(i) Their compressibility factor is never equal
to unity (Z \(\ne\) 1).

(ii) The deviations from ideal behaviour are
less at low pressures and high temperatures.

(iii) Intermolecular forces among gas
molecules are equal to zero.

(iv) They obey van der Waals’ equation,
\(pV = nRT\)