The value of Trouton's ratio (λb/Tb) for a number of substances is 21 (where, λb = molal that of vaporisation of a substance at its normal boiling point, KCal/kg. mole and Tb = normal boiling point, °K). The Kis-tyakowsky equation is used for calculation of Trouton's ratio of __________ liquids.

• A. Neither A nor B
• B. Both A & B
• C. Polar
• D. Non-polar

Answer: (B)