Q4(a) Derive the Maxwell relations of energy properties using exact differential method. (b) For a system in which the following reaction occurs 4HCl(g)+O2(g) 2H2O+2Cl2(g) Assume that there are initially 3 moles of HCl,2 moles of O2,1 mole H2O and 3 mole Cl2 Determine the mole fraction yi as function of . (c) Derive the relationship between the mole fraction of the components taking part in the reaction and the extent of the reaction