In a fuel cell, methanol is used as fuel oxygen gas is used as an oxidizer. The reaction is `CH_(3)OH(l)+(3)/(2)O_(2)(g)toCO_(2)(g)+2H_(2)O(l)` At 298K, 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^(-1)` respectively. If standard enthalpy of combusion of methanol is -726 kJ `mol^(-1)`, efficiency of the fuel cel will beA. 0.8B. 0.87C. 0.9D. 0.97

In a fuel cell, methanol is used as fuel oxygen gas is used as an oxid

1.	In a fuel cell, methanol is used as fuel oxygen gas is used as an oxidizer. The reaction is `CH_(3)OH(l)+(3)/(2)O_(2)(g)toCO_(2)(g)+2H_(2)O(l)` At 298K, 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^(-1)` respectively. If standard enthalpy of combusion of methanol is -726 kJ `mol^(-1)`, efficiency of the fuel cel will beA. 0.8B. 0.87C. 0.9D. 0.97
Answer» Correct Answer - D `Delta_(r)G=-394.4+2(-237.2)-(-166.2)` `=-702.6" kJ "mol^(-1)` Efficiency`=(Delta_(r)G)/(DeltaH)=(-702.6)/(-726)xx100=97%`

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