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In a fuel cell methanol is used as fuel ...

In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is `:`
`CH_(3)OH_((l))+(3)/(2)O_(2(g))rarr CO_2((g))+2H_(2)O_((l))`
At `298K` 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 `-394.4kJ mol^(-1)` respectively. If standard enthalpy of combustion of methanol is `-726kJ mol^(-1)`, efficiency of the fuel cell will be `:`

A

0.8

B

0.87

C

0.9

D

0.97

Text Solution

Verified by Experts

The correct Answer is:
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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