The standard oxidation potentials of Zn,Cu Ag and Ni electrodes are + 0.76 - 0.34 - 0.80 and + 0.25 V repectively which of he following reactin will provide maximum voltage

Options

A. `Cu+2Ag^(+)(aq)rarrCu^(2+)(aq)+2Ag`
B. `Zn+2Ag^(+)(aq)rarrZn^(2+)(aq)+2Ag`
C. `H_(2)Ni^(2+)(Aq)rarr2H^(+)(aq)+Ni`
D. `Zn+Cu^(2+)(aq)rarrZn^(2+)(aq)+Cu`

Answer

D

Explanation

Standard oxidition potential of Zn Cu Ag and Ni electrodes are + 076 - 0.34 - 0.80 and + 0.25 V respectively
Given `Zn^(2+) +2e^(-) rarr Zn E_(cell)=- 0.76 V`
`Cu^(2+) +2e^(-) rarr Cu , E_(Cell) =+0.34 V`
`Ag^(+) +E^(-) rarr Ag, E_(cell) =+ 0.80 V`
`Bi^(2+) +2e^(-)rarr Ni , E_(cell) =- 0.25 V`
`a Cu+2Ag(aq) rarr Cu^(2+) (aq)+2 Ag`
b `Zn+2Ag^(+)(Aq)rarr Zn^(23+) (aq)+2 Ag`
`E_(cell)=1.56 V`