Question

Fuel cells `:` Fuel cells are galvanic cells in which the chemical energy of fuel cell is directly converted into electrical energy. A type of fuel cell is a hydrogen `-` oxygen fuel cell. It consists of two electrodes made up of two porous graphite impregnated with a catalyst `(` platinum, silver, or metal oxide `).` The electrodes are placed in aqueous solution of `NaOH` . Oxygen and hydrogen are continuously fed into the cell. Hydrogen gets oxidized to `H^(o+)` which is neutralized by `overset(c-)(O)H, i.e.,` anodic reaction.

At cathode, `O_(2)` gets reduced to `overset(c-)(O)H`

Hence, the net reaction is
The overall reaction has
`DeltaH=-285.6 kJ mol^(-1)` and `DeltaG=-237.4 kJ mol^(-1)` at `25^(@)C`
If the cell voltage is `1.23V` for the `H_(2)-O_(2)` fuel cell and for the half cell `:`
A. `0.41V`
B. `0.83V`
C. `-0.41V`
D. `0.83V`

Answer 1

Correct Answer - d
Cathode `.:" "O_(2)+2H_(2)O+4e^(-) rarr 4overset(c-)(O)H`
Anode `: H_(2)+2overset(c-)(O)H rarr 2H_(2)O+2e^(-)`

`impliesE^(c-)._(cell)=1.23=0.4-(E^(c-)._(red))_(a)implies(E^(c-)._(red))_(a)=-0.83V`