Question

1. What do you mean by cells? 

2. What is the difference between primary cells and secondary cells? 

3. Fill in the following table :

	Dry Cell	Mercury Cell
Anode Cathode Electrolyte	a b e	c d f

Answer 1

1. Cells are the devices in which chemical energy is converted into electrical energy.

2.

Primary cell	Secondary cell
Electrode reaction cannot be reversed.	Electrode reaction can be reversed by an external electric energy source.
Reaction occurs only once & after use they become dead; not chargeable.	Reaction can occur many times in both directions; Rechargeable
Can’t be reused	Can be reused
Cannot be recharged	Can be recharged

3. 

• a – Zinc 
• b – Graphite 
• c – Zinc-Amalgam 
• d – HgO and Carbon 
• e – Paste of NH₄Cl and ZnCl₂ 
• f – Paste of KOH and ZnO