DANIELL
CELL
TABLE OF CONTENTS
SL CONTENT
NO
1. INTRODUCTION
2. OBJECTIVE
3. CHEMICALS REQUIRED
4. APPARATUS REQUIRED
5. THEORY
6. PREPARATION OF SALT
BRIDGE
7. PROCEDURE
8. RESULT
9. PRECAUTION
10. CONCLUSION
11. BIBLIOGRAPHY
INTRODUCTION
An electrochemical cell is a device that can generate
electrical energy from the chemical reactions occurring in it,
or use the electrical energy supplied to it to facilitate chemical
reactions.
Electrochemical cells are divided into two types:
Galvanic cell or Voltaic cell
Electrolytic cell
Galvanic cells convert chemical energy into electrical
energy, and electrolytic cells convert electrical energy into
chemical energy.
A Daniell cell is the first highly reliable and
practical electric battery, created in 19th century. In this
cell, electrons are capable of being transferred
throughout the reaction process from zinc undergoing
corrosion through paths that are electrically conductive.
The Daniell cell is a type of electrochemical
cell invented in 1836 by John Frederic
Daniell.
OBJECTIVE
To set up a simple Daniell cell using single
bridge and determine its e.m.f using an
arrangement to convert the chemical energy of
redox reaction to electrical energy.
CHEMICALS REQUIRED
1M ZnSO4
1M CUSO4
Agar-Agar
KNO3
APPARATUS REQUIRED
Two beakers
U-Tube
Connecting wires
Cotton plugs
Milli voltmeter
Sandpaper
Zinc strip
Copper strip
Watch glass
THEORY
Daniell cell consists of two half cells. One half
cell is zinc rod dipped in 1M solution of
ZnSO4 and the other half cell is copper rod
dipped in 1M CuSO4. A porous partition or a
salt bridge separates the two half cells from
each other. The electrons are connected
externally by a metal wire through a
voltmeter. Here Zn rod can act as the anode
where the oxidation takes place and Cu rod act
as the cathode where the reduction place. The
following reaction takes place at the two
electrodes.
AT ANODE:
Oxidation or lose of electrons.
Zn(s)→Zn2+(aq) +2e-
AT CATHODE:
Reduction or gain of electrons
Cu2+ (aq)+2e-→Cu(s)
The half reaction can be viewed as a
competition between the two kind of metal atoms
for electrons. In this case, zinc atoms are reactive
to lose electrons is greater than that of copper.
Both the reactions take place simultaneously at the
both half cells. In this cell, electrons travel in the
external circuit through the wire from the zinc
anode to copper cathode. If a bulb is in this cell, it
will light up. If there is a voltmeter it will show the
voltage. To complete the circuit both the positive
and negative ions move through the aqueous
solutions via the salt bridge.
The total reaction is the
sum of two half-cell reactions.
Zn(s)+Cu2+(aq) →Zn2+(aq)+Cu(s)
In this process, Zinc electrode dissolves in the
solution of ZnSO4 and reduces in size while Cu
electrode grows in size due to the deposition of
copper metal. Daniell cell generates an electric
potential of 1.1V when solution in half cells are
both 1M.
PREPARATION OF
SALT BRIDGE
Prepare a saturated solution of
KNO3 in 50ml of water in a beaker
and name it A.
Mix a few grams of Agar-Agar with
water in a beaker to form a paste
and is heated. Name the mixture as
B.
Now mix the contents of beaker A
and B together.
Fill the mixture to the salt U-tube
with the help of the dropper.
Plug both the ends of the U-tube for
preventing leakage.
PROCEDURE
Take the Copper Sulphate solution
in a clean beaker and Zinc Sulphate
in another beaker.
Clean the Copper strip and the Zinc
rod with the help of sandpaper and
dip them in Copper Sulphate and
Zinc Sulphate solution respectively.
Solutions are connected with each
other through an inverted tube i.e.
salt bridge.
Connect the Copper strip with the
positive and the Zinc rod with
negative terminals of the voltmeter.
Observe the value shown in the
voltmeter and note the reading.
RESULT
The E.M.F of the DANIELL CELL is
1.03V.
PRECAUTIONS
The concentrations of Copper
sulphate and Zinc sulphate should
neither be too low nor too high.
Clean Zinc and Copper rods with
sandpaper before use.
Note the reading only when pointer
becomes stable.
Connect Copper strips with
positive terminal of voltmeter and
Zinc rod with negative terminal.
CONCLUSION
It is free for local action, because
its negative terminal, the zinc rod
is amalgamated.
Daniell cells are no longer in use
because they take up too much
space and by modern standards are
very inefficient.
This cell will produce a little over
one volt. You can get just a little
more voltage if you make the
solutions that the electrodes are
very concentrated.
BIBLIOGRAPHY
https://www.google.com
https://byjus.com/chemistry/
daniell-cell/
https://en.m.wikipedia.org/wiki/
Daniell_cell
