Molar volume (V_m ) of a van der Waals gas can be calculated by expressing the van der Waals equation as a cubic equation with V_m as the variable. The ratio (in mol dm ⁻³ ) of the coefficient of V_m^2 to the coefficient of V_m for a gas having van der Waals constants a=6.0 dm ^6 ~atm ~mol ⁻² and b=0.060 dm ^3 ~mol ⁻¹ at 300 K and 300 atm is _____ . Use: Universal gas constant (R)=0.082 dm ^3 ~atm ~mol ⁻¹ ~K ⁻¹