The standard oxidation potential of Zn ,Cu Ag and Ni electrode are +0.76 -034 -0.80 and +0.25 V respectively which of the following reaction will provide maximum volage ?

The standard oxidation potential of Zn ,Cu Ag and Ni electrode are +0.

1.	The standard oxidation potential of Zn ,Cu Ag and Ni electrode are +0.76 -034 -0.80 and +0.25 V respectively which of the following reaction will provide maximum volage ?
Answer» `Cu + 2 Ag^(+) (aq)rarrCu^(2+)(aq)+2 Ag` `Zn+2 Ag^(+)(aq)rarrZn^(2+)(aq)+2Ag` `H_(2)+Ni^(2+)(aq)rarr2H^(+)(aq)+Ni` `Zn+2H^(+)(aq)rarrZn^(2+)(aq)+H_(2)` Solution :The reduction potential of Zn Cu Ag and Ni are : 0.76,+0.34 +0.80 and -0.25respective ly the maximum e.m.f of the cell is OBTAINED when the ELECTRODE llpotential of the anode is minimum and that of the cathode is maximum i.e Zn and Ag respecitvely `THEREFORE E.N.F =E_("cathode")E^(@)-E_("anode")^(@)` =+0.80 -(-0.76)=+1.56V thus option (b) iscorrect