NCERT 8th Class (CBSE) Science: Chemical Effects of Electric Current

Question: Why is electroplating done?

Answer: Electroplating is done for following purposes or reasons:

1. For decorating purposes: like silver or gold plating on flower vase
2. For preventing corrosion

Question: Why does zinc get attracted towards the negative terminal of the battery which is towards
the copper plate?

Answer: In battery, the movement of electron takes place from cathode to anode. This shows that cathode is electron rich while anode is electron deficient. Since Zinc behave as anode therefore positively charged and get attracted towards negative terminal of battery.

Question: How can you prove conducting properties of substances when the current is very small and bulb does not glow?

Answer: By using magnetic compass.

Question: Why is chrome plating is popular in the industries?

Answer: This is because of its low cost, easy processing and the wide ranges of applications.

Question: What are the factors on which the amount of metal deposited on cathode during electroplating depend on?

Answer: The factors on which the amount of metal deposited on cathode during electroplating depends on are:

1. The time for which the current passes through electrolyte
2. The magnitude of current passes through electrolyte

Question: What is electro deposition?

Answer: The electroplating is also used to increase the thickness of the part of machines, to make them the just right size this phenomenon is called electro deposition.

Question: What galvanization?

Answer: The process of dipping metal into zinc solution to for layer of zinc over another metal is called galvanization. Zinc coated iron is called Galvanized Iron (GI). This iron is used in water taps (GI pipes), since they have high resistance to corrosion.