In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is
CH₃OH(l) + 3/2O_2 CO₂ (g) + 2H₂O (l)
At 298K standard Gibb’s energies of formation for CH₃OH(l), H₂O(l) and CO₂ (g) are -166.2, -237.2 and -394.4 kJ mol^−1 respectively. If standard enthalpy of combustion of methanol is -726 kJ mol^−1, efficiency of the fuel cell will be