The standard reduction potential for the half-cell, `NO_(3(aq.))^(-)+2H_((aq.))^(+)+e^(-)rarrNO_(2(g))+2H_(2)O` is `0.78V`.
(i) Calculate the reduction potential in 8M `H^(+)`.
(ii) 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 8M `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+0.1062=0.8862V):}`
ii) In case of netural solution, concentration of `[H^(+)]=10^(-7)M` and conc. of all other species are unity, then
`E_(RP),=E_(RP)^(0)+(0.059)/(1)log_(10)[H^(+)]^(2)`
`=0.78+(0.059)/(1)log_(10)(10^(-7))^(2)`
`=0.78+(-0.826)=-0.046V`