Question 3:
Rohani found a rusted iron nail. Using your knowledge of electrolysis, describe a simple way to prevent the rusting of the iron nail.
Answer:
The rusting of the iron nail can be avoided by electroplating the iron nail with copper through electrolysis under the following conditions:
• iron nail is made the cathode
• pure copper is made the anode
• copper(II) sulphate solution is used as the electrolyte
• electric current is supplied by an electrical source to carry out the electrolysis
Rohani found a rusted iron nail. Using your knowledge of electrolysis, describe a simple way to prevent the rusting of the iron nail.
Answer:
The rusting of the iron nail can be avoided by electroplating the iron nail with copper through electrolysis under the following conditions:
• iron nail is made the cathode
• pure copper is made the anode
• copper(II) sulphate solution is used as the electrolyte
• electric current is supplied by an electrical source to carry out the electrolysis
Question 4:
You are given three potatoes, three iron nails, three copper rods, light bulb and connecting wires with crocodile clips. Using these materials, design a simple chemical cell with the following features:
(a) simple chemical cell that can light up a light bulb with maximum brightness.
(b) simple chemical cell that can last the longest when lighting up a light bulb.
Answer:
(a)
Three simple chemical cells, each made up of a potato with an iron nail and a copper rod poked into the potato and connected in series as in the figure below.

(b)
Three simple chemical cells, each made up of a potato with an iron nail and a copper rod poked into the potato and connected in parallel.
You are given three potatoes, three iron nails, three copper rods, light bulb and connecting wires with crocodile clips. Using these materials, design a simple chemical cell with the following features:
(a) simple chemical cell that can light up a light bulb with maximum brightness.
(b) simple chemical cell that can last the longest when lighting up a light bulb.
Answer:
(a)
Three simple chemical cells, each made up of a potato with an iron nail and a copper rod poked into the potato and connected in series as in the figure below.

(b)
Three simple chemical cells, each made up of a potato with an iron nail and a copper rod poked into the potato and connected in parallel.