Fuel cells are galvanic cells in which the chemical energy of fuel is directly converted into electrical energy. 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 nad hydrogen are continuously fed into the cell. Hydrogen gets oxidized to `H^(oplus)` which is neutralized by `overset(Θ)(OH)`, ie., anodic reaction.
`H_(2) hArr 2H^(oplus) + 2e^(-)`
`2H^(oplus) + 2 overset(Θ)(OH) hArr 2H_(2)O`
`H_(2) + 2 overset(Θ)(OH) hArr 2H_(2)O + 2e^(-)`
At cathode, `O_(2)` gets reduced to `overset(Θ)(OH)` i.e., `O_(2) + 2H_(2)O + 4e^(-) hArr overset(Θ)(4)OH`
Hence, the net reaction is `2H_(2) + O_(2) hArr 2H_(2)O`
The overall reaction has `Delta H= -285.6kJ mol^(-1) and Delta G= -237.4kJ mol^(-1) " at " 25^(@)C`
Suppose the concentration of hydroxide ion in the cell is doubled, then the cell voltage will be

Options

A. Reduced by half
B. increased by a factor of 2
C. Increased by a factor of 4
D. Unchanged

Answer

D

Explanation

`E_("cell")` is independent of `[overset(Θ)(O)H]` in this case