What is the single electrode potential of a half-cell for zinc electrode dipping in 0.01 M `ZnSO_(4)` solution at `25^(@)C` ? The standard electrode potential of `Zn//Zn^(2+)` system is 0.763 volt at `25^(@)C`.
We know that, `E_(o x)=E_(o x)^(@)-0.0591/n log_(10) ["ion"]`
Putting the value of `E_(o x)^(@)=0.763 V, n=2` and `[Zn^(2+)]=0.01 M`,
`E_(o x)=0.763-0.0591/2 log_(10) [0.01]`
`=0.763-0.02955xx(-2)`
`=(0.763+0.0591)` volt `=0.8221` volt
Correct Answer - D
A acts as cathode and B acts as anode because reduction potential of A is more.
Anode is B `implies` is negative electrode.
`implies` electrons flow from...
We know that, `E_("red")=E_("red")^(@)+0.0591/n log_(10) ["ion"]`
Putting the value of `E_("red")^(@)=0.34 V, n=2` and `[Cu^(2+)]=0.1 M`
`E_("red")=0.34+0.0591/2 log_(10) [0.1]`
`=0.34+0.02955xx(-1)`
`=0.34-0.02955=0.31045` volt
The cell reaction is
`Zn+2Ag^(+) rarr 2Ag+Zn^(2+)`
`E_(o x)^(@)` of `Zn =0.76` volt
`E_("red")^(@)` of `Ag=0.80` volt
`E_(cell)^(@)=E_(o x)^(@)` of `Zn+E_("red")^(@)` of `Ag=0.76+0.80=1.56` volt
We know that, `E_(cell)=E_(cell)^(@)-0.0591/n"log" (["Products"])/(["Reactants"])`
`=E_(cell)^(@)-0.0591/2"log"...
The cell reaction is
`M+3Ag^(+) rarr 3Ag+M^(3+)`
Applying Nernst equation,
`E_(cell)=E_(cell)^(@)-0.0591/3"log" ([M^(3+)])/([Ag^(+)]^(3))`
`0.42=E_(cell)^(@)-0.0591/3"log"((0.0018))/((0.01)^(3))=E_(cell)^(@)-0.064`
`E_(cell)^(@)=(0.42+0.064)=0.484` volt
`E_(cell)^(@)=E_("Cathode")^(@)-E_("Anode")^(@)`
or `E_("Anode")^(@)=E_("Cathode")^(@)-E_(Cell)^(@)`
`=(0.80-0.484)=0.32` volt