1.

The emf `(E^(@))` of the following cels are : `Ag|Ag^(+) (1 M)||Cu^(2+) (1 M)|Cu, E^(@)=-0.46` volt `Zn|Zn^(2+) (1 M)||Cu^(2+) (1 M)|Cu, E^(@)=+1.10` volt Calculate the emf of the cell : `Zn|Zn^(2+) (1 M)||Ag^(+) (1 M)|Ag`

Answer» `Zn|Zn^(2+) (1 M)||Ag^(+) (1 M)|Ag`
`E_(cell)=E_(o x(Zn//Zn^(2+)))+E_(red (Ag^(+)//Ag))`
With the help of the following two cells, the above equation can be obtained :
`Ag|Ag^(+) (1 M)||Cu^(2+) (1M)|Cu, E^(@)=-0.46" volt"`
or `Cu|Cu^(2+) (1 M)||Ag^(+) (1 M) |Ag, E^(@)" will be "+0.46" volt"`
or `+0.46=E_("ox"(Cu//Cu^(2+)))+R_("red "(Ag^(+)//Ag))` ...(i)
`Zn|Zn^(2+) (1 M)||Cu^(2+)|Cu, E^(@)=+1.10" volt"`
`+1.10=E_(o x (Zn//Zn^(2+)))+E_(red (Cu^(2+)//Cu))` ...(ii)
Adding eqs. (i) and (ii),
`+1.56=E=E_("red "(Ag^(+)//Ag))+E_(o x (Zn//Zn^(2+)))+E_("red "(Cu^(2+)//Cu))`
since, `E_(o x(Cu//Cu^(2+)))=-E_("red "(Cu^(2+)//Cu))`
So, `+1.56=E_(o x (Zn//Zn^(2+)))+E_("red "(Ag^(+)//Ag))`
Thus, the emf of the following cell is
`Zn|Zn^(2+)(1 M)||Ag^(+) (1 M)|Ag` is `+ 1.56` volt


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