Electrochemical cell lab Aim :- To find out the feasibility of a redox reaction by looking at the cell potential of the reaction .

Data processing

Experiment 1

Zn(s) -> Zn2+ (aq) + 2e- (aq)

Cu2+ (aq) + 2e- (aq) -> Cu (s)

Cu2+ (aq) + Zn(s) -> Cu(s) + Zn2+ (aq)

Experiment 2

Cu(s)  -> Cu2+ (aq)+ 2e- (aq)

Ag+(aq)  + e- (aq) -> Ag(s)

Cu(s) + 2Ag+ (aq) -> Cu2+ (Aq) + 2Ag (s)

Experiment 3

Zn(s) -> Zn2+ (aq) + 2e- (aq)

Ag+ (aq)  + e- (aq)-> Ag(s)

Zn(s) + 2Ag+ (aq) -> Zn2+ (aq) + 2Ag (s)

The table below shows the literature values for the respective cell potential

Error percentage  

= (|difference between the literature and experimental value|)/(the literature value )x100

= (|0.34V - 0.99V|)/(0.34V) x100

= 191.17%

We can similarly find the error percentages for other cell potentials also

The table below shows the respective error percentages of each of the cell potential

Theory

Electrochemical cells

In an electrochemical cell, electricity is produced through chemical reactions. There consist two electrodes: - the negative electrode and the positive electrode. At the negative electrode the more reactive metal is kept which undergoes oxidation, since this electrode undergoes oxidation, this electrode undergoes oxidation, this electrode is called anode.  During oxidation the metal releases the electrons to form ions. The electrons then travel to the other cell, through an external wire connected in series to a bulb to the positive terminal. At the positive terminal the electrons reduce with the metal ion on the positive terminal to form the respective metal. Since reduction takes place at this electrode, this electrode is referred to as cathode. The direction of the conventional flow of the current flows from cathode to anode since the electrons from the metal that is oxidized in the anode moves to cathode.