Assuming the water vapour to be a perfect gas. When 1 mol of water at 100°C and 1 bar pressure is converted to ice at 0°C, the change in internal energy is-

(The enthalpy of fusion of ice = 6.00 kJ mol^-1 , heat capacity of water = 4.2 J/g°C)

1. 13.56 kJ mol^-1

2. -12.16 kJ mol^-1

3. -13.56 kJ mol^-1

4. 12.16 kJ mol^-1