Form 5 Chemistry – Industrial Applications of Electrolysis
Name: ____________________
Class: ________ (
) Date:_______________
(a) Electroplating
 Electroplating is a process to plate one metal with a thin layer of another metal
by electrolysis

1)
Electroplating is carried out in an electrolytic cell
Plating metal is the anode
2)
Electroplated object is the cathode
3)
Electrolyte is an aqueous solution containing the ions of the plating metal
Example:

Plating metal (Cu) is oxidized to form cations (Cu2+)

Ions of the plating metal (Cu2+) is reduced and the metal (Cu) is deposited on
the surface of electroplated object (metallic ring)
Is there any observable change in the solution during the electroplating process?
Form 5 Chemistry – Industrial Applications of Electrolysis
Exercise:
An iron bolt is nickel-plated using the set-up shown below:
Which of the following statements concerning the set-up are correct?
(1) The nickel electrode loses electrons to form nickel(II) ions
(2) Reduction occurs at the iron bolt
(3) The colour intensity of the solution remains unchanged.
A.
C.
(1) and (2) only
(2) and (3) only
B.
D.
(1) and (3) only
(1), (2) and (3)

How to obtain a smooth and firm metal layer on the electroplated object?
1)
Temperature, pH and concentration of ions in the electrolyte should be kept
constant
2)
Oil dirts on the surface of electroplated object should be removed before
electroplating
3)
Low current and voltage is used