In a fuel cell, methanol is used as fuel and oxygen gas is used as an oxidiser. The reaction is
CH3OH(l) +3/2 O2(g)→ CO2(g)+2H2O(l)
At 298 K standard Gibb's energies of formation for CH3OH(l),H2O(l) and CO2 (g ) are -166.2, -237.2 and -394.4kJ mol-1 respectively. If standard enthalpy of combustion of methanol is -726 kJ mol-1, efficiency of the fuel cell will be
(a) 80% (b) 87% (c) 90% (d) 97%
