2. 1cm3 of water at its boiling point absorbs 540 calories of heat to become steam with a

volume of 1671 cm³ .If the atmospheric pressure = 1.013 x 10⁵ N/m³ and the mechanical equivalent of heat = 4.19 J/calorie , the energy spent in this process in overcoming intermolecular forces is

(a)  540 cal                               (b)  40 cal

(c)   500 cal                               (d)  Zero

Ans. c