Which from following process involves zero work done?

Calculate the constant external pressure required to expand 2 moles of an ideal gas from volume $15 \mathrm{dm}^3$ to $20 \mathrm{dm}^3$ if amount of work done is -600 J .

Calculate the enthalpy of vaporisation of ethanol if 11.5 g of ethanol is completely vaporised by supplying 11.8 kJ of heat.

Calculate the enthalpy change of vaporisation of benzene if 13 gram of benzene vaporised by supplying 5.1 kJ of heat.