Two half cell reactions are given below : CO ³⁺+ e ⁻ Co ²⁺, E ^ Co ²⁺ / Co ³⁺=-1.81 ~V 2 Al ³⁺+6 e ⁻ 2 Al ( s ), E ^ o Al / Al ³⁺=+1.66 ~V The standard EMF of a cell with feasible redox reaction will be :

Step-by-step solution

The cell reaction is written as : aligned & E ^ Co ²⁺ / Co ³⁺=-1.81 ~V ( SOP ) & E ^ Co ³⁺ / Co ²⁺=+1.81 ~V (SRP) & E _ A / / Al ³⁺ ^ =+1.66 ~V ( SOP ) & E _ Al ³⁺ / Al ^ =-1.66 ~V ( SRP ) & aligned Here E ^ is given in standard Reduction Potential Co ³⁺ / Co will undergo reduction acting as cathode and Al ³⁺ / Al will undergo oxidation acting as anode. aligned E _ cell ^ & = E _ cathode (Red.) ^ - E _ Anode (oxide) ^ E _ cell ^ & =1.81-(-1.66) E _ cell ^ & =+3.47 ~V aligned