The standard reduction potential for the half cell `:`
`NO_(3)^(c-)(aq)+2H^(c-) +e^(-) rarr NO_(2)(g)+H_(2)O` is `0.78V`.
`a.` Calculate the reduction potential in `8M H^(o+)`.
`b.` What will be the reduction potential of the half cell in a neutral solution ? Assume all the other species to be at unit concentration.

Explanation

(i) In `8 M H^(+)` solution, conc. of all other species in unity.
`E_(RP) = E_(RP)^(@) + (0.059)/(1)log_(10)[H^(+)]^(2)`
`= 0.78 + 0.059log_(10)(8)^(2)`
`= 0.78 xx 0.1062 = 0.8862 V`
(ii) In case of neutral solution, concentration of `[H^(+)] = 10^(-7) M` and conc. of all other species are unity, then
`E_(RP) = E_(RP)^(@) + (0.059)/(1)log_(10)[H^(+)]^(2)`
`= 0.78 + (0.059)/(1)log_(10)(10^(-7))^(2)`
`= 0.78 + (-0.826) = -0.046 V`