vander walls equation and critical phenomenon

In vander waal's equation of the gas law the constant of a is a measure of

Which of the following statement (s) is true I- Slpe of isotherm at critical point is maximum II - Larger is the value of T_(C) easier is the liquification of gas. III- Vander walls equation of state is applicable below critical temperature at all pressure.

Write the vander waals equation for 'n' mol gas.

Find volume of 2 moles of a vander waals gas at critical pressure & critical temperature. Given for gas : [P_(C)=2atm and T_(C)=300K]

Which of following statements (s) is true I -Slope of isotherm at critical point is maximum. II-Larger is the value of T_(c) easler is the liquification of gas. III-Vander waals equation of state is applicable below critical temperature at all pressure.

Obtain the equation for critical angle.