Van der Waals found that two assumptions made by the kinetic theory of gases were wrong. These were as follows : 1. The gas molecules are point particles without significant volumes. If this assumption (s correct, the pressure vs volume graph of experimental data (real gas) and that theoretically calculated from Boyle's law (ideal behaviour) should coincide. However, 1hi& is not so. This assumption is valid only under ordinary conditions of temperature and pressure. 2. The forces of attraction between the gas molecules are negligible. If this assumption is correct, the gas will never liquify. However, we know that gases get liquified when cooled and compressedHence, option 'C' is correct