Electochemistry
Electroplating Teaching Notes
OVERVIEW
EQUIPMENT AND MATERIALS
Preparation of 1 M solution of CuSO4:
There are several key principles for students to
understand about the electroplating process:
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For CuSO4 anhydrous – dissolve 160 g to a total
volume of 1 L
During electroplating, the same metal – the
plating metal - undergoes both oxidation and
reduction. The oxidation reaction provides the
source of the metallic ions; the reduction
reaction is the actual plating of the metal on the
desired object.
The object to be plated, a nail for example, must
be connected to the NEGATIVE post of the
battery. This will cause the nail to gain a
negative charge which attracts the positive
metal ions from the solution. Reduction will
occur on the surface of the nail, making it the
CATHODE.
For CuSO4  5H2O – dissolve 250 g to a total volume
of 1 L
PROCEDURE
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RESULTS
Students should be able to follow the flow of
electrons. The negative post of the battery
provides the initial supply of electrons that
allow reduction to occur at the iron nail.
Electrons return to the battery from the anode,
where the copper strip undergoes oxidation.
An electrolytic solution containing the plating
ions is the final key requirement of the set-up.
The copper strip (anode) is required to replenish
the ions removed from solution at the cathode.
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Students should note that the plated item slowly
develops a coating; this may be difficult to see,
however, through the blue copper(II) sulfate
solution. The finished product should clearly
show a coating, however.
CONCLUSIONS AND QUESTIONS
1.
There are many variations and options that can be
used for this experiment. Some alternate ideas:
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The cleaner the object to be plated, the better
the results.
Write the half-reaction that occurs at the anode of
the electrolytic cell. Identify the reaction as either
oxidation or reduction.
Cu(s)  Cu2+(aq) + 2e-
plate a copper penny with zinc
plate quarters with copper
Oxidation occurs at the anode
An option to having all students perform the
electroplating lab and other experiments in this unit
is to divide the class into groups. Each group would
them prepare one experiment as a demonstration for
the rest of the class. Posters could be made to help
with the presentation. Suggested lab
demonstrations:
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The electrolysis of water
Electroplating
An electrochemical cell
Electrochemistry: Electroplating Teaching Notes
2.
Write the half-reaction that occurs at the cathode of
the electrolytic cell. Identify the reaction as either
oxidation or reduction.
Cu2+ (aq) + 2e-  Cu(s)
Reduction occurs at the cathode
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3.
Write a descriptive paragraph or two that explains
both the flow of copper ions and electrons through
the system.
Copper ions are produced at the anode when the
solid copper strip undergoes oxidation. These ions
go into the electrolytic solution, which also contains
Electrochemistry: Electroplating Teaching Notes
copper ions. The electrons released during this
oxidation will travel to the battery.
Electrons flowed from the battery to the iron nail,
causing it to pick up a negative charge. The positive
copper ions from the solution become attracted to
the negative charge on the iron nail. When the ions
contact the nail they undergo reduction, forming
solid copper which is deposited on the nail.
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