The standard oxidation potential of `Ni//Ni^(2+)` electrode is `0.236 V`. If this is combined with a hydrogen electrode in acid solution, at what `pH` of this solution will be measured e.m.f. be zero at `25^(@)C`? Assume that `[Ni^(2+)] = 1 M` and `P_(H_(2)) = 1 atm`.

Answer

D

Explanation

`NirarrNi^(2+)+2e,E_(OP)^(@)=0.236V`
`2H^(+)+2erarrH_(2),(E_(RP)^(@)=0)/(E_(cell)^(0)=0.236V)`
`E_(cell)=E_(cell)^(@)+(0.059)/(2)log_(10).([H^(+)]^(2))/([Ni^(2+)])`
`0=0.236+(0.059)/(2)log_(10)[H^(+)]`
`-log_(10)H^(+)=4thereforepH=4`