3B Scientific Leclanche Cell User Manual

3B SCIENTIFIC3B SCIENTIFIC

3B SCIENTIFIC®

3B SCIENTIFIC3B SCIENTIFIC

U14330 Leclanché cell

Instruction sheet

8/05 ALF

PHYSICSPHYSICS

PHYSICS

PHYSICSPHYSICS

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®

... going one step further

1 Carbon electrode with 4-mm socket
2 4-mm socket
3 Lid
4 Zinc electrode
5 Glass vessel

1. Safety instructions

• Caution! Heavy metal salts are toxic.

• Safety goggles are a must when working with acids or

alkalis.

• Students must always be thoroughly informed about
the hazards of the chemicals used.

• Leaking fluid can cause permanent stains and holes
in clothing.

• The apparatus must be thoroughly cleaned after the
experiment.

• Applicable regulations must be strictly adhered to
when disposing of the chemicals.

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2. Description, technical data

The model for a dry cell battery was invented around
1860 by French chemist Georges Leclanché. The cell named
after him, which continues to be the most common bat­tery even today, uses manganese dioxide and is not re­chargeable. The Leclanche cell consists of a cylindrical
zinc electrode, a carbon electrode, a ceramic cell and a
glass vessel. The cell as supplied has no filling. When
filled, the Leclanche cell provides a voltage of
approx. 1.5 V.
Connections: via 4-mm sockets
Dimensions: 175 mm high, 65 mm Æ

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2.1 Scope of delivery

1 Glass vessel
1 Clay cylinder
1 Lid
1 Zinc electrode with socket
1 Carbon electrode with socket

3. Principle

The combination of two half-cells for the purpose of
converting chemical energy into electrical energy is called
a galvanic cell. In a Leclanche cell, a zinc electrode forms
the negative pole and a carbon rod with the manganese
dioxide (MnO2) coating forms the positive pole. In the
space between, ammonium chloride is used as an elec­trolyte. The ensuing chemical reaction chiefly results from
the oxidation of zinc and reduction of manganese diox­ide.
Oxidation:

+



Zn+2 NH Zn NH 2e 2H

Reduction:

2 MnO 2 H 2 e Mn O H O

Redox reaction:

Zn+2 NH 2 Mn O Zn NH Mn O H O

→++

43

++→ +

2232

+

42 3 232

()



−

+

+→ ++

+

2

2



()



+

−

+

2

2

The reactions shown here are simplified. They are far
more complicated in reality. The reaction ceases when
the manganese dioxide has been used up.

4. Operation

• To construct a Leclanché cell requires the following:
Ammonium chloride solution (NH4Cl), approx. 20%
Manganese dioxide (powder) (MnO2)
Graphite (powder)

• Mix the manganese dioxide powder and some graph­ite powder in a beaker. Then add the ammonium
chloride solution and stir the mixture to form a paste.

• Position the zinc electrode into the glass vessel and
place the ceramic cylinder inside.

• Position the carbon electrode in the centre of the
ceramic cylinder and fill up all remaining space with
the manganese dioxide paste.

• Fill up the glass vessel with the 20% ammonium chlo­ride solution and cover it with the lid.

• The apparatus and electrodes must be thoroughly
cleaned immediately after the experiment.

• Chemicals which cannot be reused must be stored in
special vessels and disposed of in an orderly fashion
afterwards, strictly adhering to applicable regulations.

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Fig. 1: Leclanché cell

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1 Ceramic cylinder
2 Manganese dioxide coating
3 Carbon electrode
4 4-mm socket
5 Glass vessel
6 Zinc cylinder
7 Ammonium chloride

solution

3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com • Technical specifications subject to change

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