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In a fuel celll, methanol is used as a f...

In a fuel celll, methanol is used as a fuel and `O_(2)` is used as oxidizer. The standard enthalpy of combustion of methanol is -726 kJ `mol^(-1)`. The standard free energies of formation of `CH_(3)OH(I), CO_(2)(g) and H_(2)O(I)` are -166.3, -394.4 and -237.1 kJ `mol^(-1)` respectively.
The efficiency of the fuel cell will be

A

`90%`

B

`97%`

C

`80%`

D

`87%`

Text Solution

Verified by Experts

The correct Answer is:
B
Efficienty `=(Delta G^(@))/(Delta H^(@))xx100`
`CH_(3)OH_((l))+(3)/(2)O_(2(g))rarr CO_(2(g))+2H_(2)O_((l))`
`Delta G^(@)=-702.6 kJ mol^(-1)`
`therefore` efficiency `=(-702.6)/(726)xx100=97%`
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