In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction isCH_(3)OH(l)+(3)/(2)O_(2)(g)rarrCO_(2)(g)+2H_(2)O(l) At 298 K standard Gibb's 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^(-1) respectively. If standard enthalpy of combustion of methanol is -726 kJ mol^(-1), efficiency of the fuel cell will be

In a fuel cell methanol is used as fuel and oxygen gas is used as an o

1.	In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction isCH_(3)OH(l)+(3)/(2)O_(2)(g)rarrCO_(2)(g)+2H_(2)O(l) At 298 K standard Gibb's 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^(-1) respectively. If standard enthalpy of combustion of methanol is -726 kJ mol^(-1), efficiency of the fuel cell will be
Answer» 0.8 0.87 0.9 0.97 Solution :`CH_(3)OH(l)+(3)/(2)O_(2)(g)rarrCO_(2)(g)+2H_(2)O(l)` `DeltaG_(r)=DeltaG_(F)(CO_(2)(g)+2DeltaG_(f)(H_(2)O(l))-DeltaG_(f)(CH_(3)OH(l))` `-(3)/(2)DeltaG_(f)(O_(2)(g))` `=-394.4+2(-237.2)-(-166.2)-0` `=-394.4-474.4+166.2=-868.8+166.2` `DeltaG_(r)=-702.6 kJ` % EFFICIENCY = `(702.6)/(726)xx100=97%`.