SAN THOME ACADEMY

Session 2023-2024

CHEMISTRY
Investigatory project on

“Electrochemical Cell”
SUBMITTED BY :- SUBMITTED TO :-
Harshvardhan Singh Chouhan Mr. Puneet Upadhyay

12th A
Roll no :-

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 ACKNOWLEDGEMENT

I would like to convey my thanks to Mr. Puneet

Upadhyay sir, my Chemistry teacher and
principal, San Thome Academy for their
immense help and guidance in the completion of
my project. It is only due to their efforts that my
project could be completed successfully. This
report is submitted as a part of practical
examination included in curriculum of CBSE for
all India senior secondary examination to be
held in the year 2023- 2024.

Candidate :-
Harshvardhan Singh Chouhan

Chemistry teacher :-
Mr. Puneet Upadhyay

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 Certificate

T his is to certify that master Harshvardhan

Singh Chouhan of class 12th-A, of San
Thome Academy, Dewas, has completed this
project under my supervision. He has taken keen
interest and shown utmost sincerity in completion
of this project. He has successfully completed the
“Investigatory Project work in Chemistry” on the
topic “Electrochemical Cell” up to my satisfaction.

Guided by :- Mr. Puneet Upadhyay

(Principal Sign) (External Examiner)

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 DECLARATION

T his project work in Chemistry is a confined

piece of work done by me under the
guidance and supervision of Mr. Puneet
Upadhyay sir and has not been previously formed
bases of degree, diploma or any other similar title
or any other negotiation.

Submitted by :- Harshvardhan Singh Chouhan

Class :- 12th A

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 INDEX

S. No. Content Page No.

1. Introduction 6
2. Representation of Cell 7
3. Experimental Setup 8
4. Salt Bridge & Functions 9
5. Standard EMF 11
6. Some Important Features 13
7. Procedure 15
8. Observations 16
9. Conclusion 17
10. Bibliography 18

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 INTRODUCTION

Electro Chemical Cell

Whenever a redox reaction is allowed to take
place directly in a single beaker, it is found that the
solution becomes hot. For example, when zinc is
placed in a copper solution, the solution is found to
be warmer as the reaction proceeds according to
the equation.
Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)
Similar results are observed when a rod of copper
is placed in silver solution. The reaction takes
place as follows:
Cu(s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag(s)
Thus, we conclude that whenever a redox reaction
takes place directly in a single beaker, chemical
energy in the form of heat is produced. By suitable
means it is possible to bring out the redox reaction
indirectly so as to convert the chemical energy into
the electrical energy.

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Representation of an Electrochemical
Cell
An electrochemical cell is represented in a manner
as illustrated below.
Zn(s)/Zn2+(aq) || Cu2+(aq)/Cu(s)
i.e. by convention, the electrode on which
oxidation takes place is written on the left-hand
side and the other electrode on which reduction
takes place is written on the right-hand side.

The electrode of the left-hand side is written by

writing the symbol of the metal first followed by the
symbol of the ion with its concentration in brackets.

The electrode on the right-hand side is written by

first writing the ion along with its concentration in
brackets followed by the symbol of the metal.

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 Experimental Setup
A zinc rod is placed in the zinc sulphate solution
taken in a beaker. A copper rod is placed in the
copper sulphate solution taken in another beaker.
The two rods are connected by a wire with
galvanometer (external circuit) and two solutions
are connected by a salt bridge (internal circuit).

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 Salt Bridge & its
Functions
A salt-bridge is a U-shaped tube containing
concentrated solution of an inert electrolyte like
KCl, KNO3 , K2SO4 etc. An inert electrolyte is one
whose ions do not take part in the redox reaction
and also do not react with electrolyte used. The
function of the salt bridge is to allow the movement
of the ions from one solution to the other without
mixing of the two solutions. Thus, whereas the
electrons flow in the outer circuit in the wire, the
inner circuit is completed by the flow of ions from
one solution to the other through the salt bridge
moreover, it helps to maintain the electrical
neutrality of the solution of the two half cells.
Thus, the main functions of the salt bridge are:
• To complete the electrical circuit by allowing
the ions to flow from one solution to the other
without mixing of the two solutions.
• To maintain the electrical neutrality of the
solutions in the two half cells.
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Let us see what would happen if the salt bridge
were not used in the cells show in the following
diagram. Electrons are given out by the zinc
electrode where they will neutralize some of the
Cu2+ions of the solution. Thus SO42-ions will not
leave and the solution will acquire a negative
charge. At the same time, Zn2+ ions produced from
zinc plate will enter ZnSO4 solution. After some
time, the flow of electrons will stop and hence the
current stops flowing.

- Electrochemical cells can be found in nature.

- Electrochemical cells enable sustainable energy

solutions.

- The first electrochemical cell was invented by

Alessandro Volta.
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 Standard EMF of an
Electrochemical cell
An electrochemical cell is based on reaction which
can be split into the two half reactions:
• Oxidation half reaction
• Reduction half reaction
Standard EMF of the cell: Where,
Ecell = Electrode Potential of the cell
Ecathode = Electrode Potential of the oxidation half
reaction
Eanode = Electrode Potential of the oxidation half
reaction
According to Nernst Equation, the relation
between concentration of electrode and the
standard electrode potential can be given as:
Ecell = Ecathode - Eanode
E = Eo – 0.059/n Log( [M]/ [Mn+])
Where,
E = Electrode Potential at non-standard conditions

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Eo = Electrode potential at standard conditions
N = Number of electrons transferred in the
equation
[M] = concentration of the metal
[Mn+] = concentration of metal ion
Standard Electrode(reduction) potentials of some
elements :- (Electrochemical Series)

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 Some Important
Features
• The electrode at which oxidation takes place
is called the anode. The electrode at which
the reduction takes place is called the
cathode.
• Since electrons are produced at the zinc
electrodes, this electrode is rich in electrons,
which pushes the electrons into the external
circuit and hence it is designated as the
negative pole. The other electrode, i.e. the
copper electrode is in the need of electrons
for the reduction of Cu2+ ions into the Cu.
• The electrons flow from the negative pole to
the positive pole in the external circuit.
However, conventionally, this current is set to
flow in the opposite direction.
• The oxidation of Zn into ions produces excess
of Zn2+ ions in the left beaker. This creates
an unbalanced positive charge in the solution.
To maintain electrical neutrality of the solution
in the two beakers, the cations and anions
move through the salt bridge.
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 • As copper from copper sulphate solution is
deposited on the copper electrode and
sulphate ions migrate to the other side, the
concentration of the copper sulphate solution
decreases. As the cell operates consequently,
the current falls.

Evidently, the weight of the copper rod will

increase while that of zinc rod will decrease as the
cell works.

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 Procedure
➢ Take two clean beakers.
➢ In one beaker take 0.5M copper sulphate
solution and in the other take 0.5M zinc sulphate
solution.
➢ Take a copper strip and clean it using a
sandpaper.
➢ Dip the copper strip into the beaker containing
the 1M copper sulphate solution.
➢ Similarly, take a zinc strip and clean it using a
sandpaper.
➢ Then dip into the beaker containing 1M zinc
sulphate solution.
➢ Take a salt bridge and connect the two
solutions using the salt bridge.
➢ Take a voltmeter and connect the copper strip
to the positive terminal and the zinc strip to the
negative terminal using connecting wires.
➢ Note the positive of the pointer in the voltmeter
and record the reading.
➢ Repeat the experiment by taking different
concentration of zinc sulphate and the copper
sulphate solutions.

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 Observation

S. No. MCuSO4 MZnSO4 EMF

1 0.5 0.5 0.98 V
2 0.5 0.25 0.81 V
3 0.25 0.25 0.90 V

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 CONCLUSION

With these observations, we conclude that EMF

of the cell increases with decreases in the
concentration of the electrolyte around the
anode and the increase in the concentration of
the electrolyte around the cathode.

Without Electrochemical cells, electronic world

would be nearly incomplete!

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 BIBLIOGRAPHY
This project would be nearly incomplete if I had
not used the information given in the following
websites.
My special thanks to the up loader of information
on these websites:-

➢ www.google.com

➢ www.wikipedia.org

➢ www.scribd.com

Class 12 Chemistry NCERT also played a crucial

role in making of this project.

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