In afuel cell, methanol is used as fuel and oxygen is used as an oxidiser.The reaction is : CH_(3)OH(l) + 3/2O_(2)(g) to CO_(2) (g) + 2H_(2)O(l) At 298 K, standard Gibbs energies of formation for CH_(3)OH(l), H_(2)O(l) and CO_(2)(g) are -166.2, -237.2 and -394.4 kJ/mol respectively.If standard enthalpy of combustion of methanol is -726 (kJ)/(mol), efficiency of the fuel cell will be

In afuel cell, methanol is used as fuel and oxygen is used as an oxidi

1.	In afuel cell, methanol is used as fuel and oxygen is used as an oxidiser.The reaction is : CH_(3)OH(l) + 3/2O_(2)(g) to CO_(2) (g) + 2H_(2)O(l) At 298 K, standard Gibbs energies of formation for CH_(3)OH(l), H_(2)O(l) and CO_(2)(g) are -166.2, -237.2 and -394.4 kJ/mol respectively.If standard enthalpy of combustion of methanol is -726 (kJ)/(mol), efficiency of the fuel cell will be
Answer» 0.8 0.87 0.9 0.97 Solution :`CH_(3)OH(l) + 3/2O_(2)(g) to CO_(2)(g) + 2H_(2)O(l) Delta_(F)H = -726 KJ"mol"^(-1)` `Delta_(r)G = Delta_(f)G_("products") - SigmaDelta_(f)G_("REACTANTS")` `= [ Delta_(f)G_(co_(2)) + 2 xx Delta_(f)G_(H_(2)O)] - [ Delta_(f)G(CH_(3)OH) + 3/2Delta_(f)G_(O_(2))]` ` = [-394.4 + 2 xx (-237.2)] - [-166.2 + 3/2(0)]` ` = -702.6 kJ"mol"^(-1)` % Efficiency = `(Delta_(f)G)/(Delta_(f)H) xx 100 = (-702.6)/(-723) xx 100` 96.77 % aaprox 97%