Question

The acid used in lead storage battery is:
A.Nitric acid
B.Sulphuric acid
C.Hydrochloric acid
D.Phosphoric acid

Answer 1

Hint: A lead storage battery is also known as lead acid battery. The battery makes use of the electrochemical reaction which converts chemical energy into electrical energy by losing electrolytes when dissolved in sulphuric acid.

Complete step by step answer:
Lead storage batteries were invented in 1859 by a French physicist, Gaston Plante. These are highly reliable as they have a minimal life. They are heavy to ship and made up of many toxic materials that require certain methods of removal by the end of their life. Their response time is better and generates moderate power density. They can accept or supply energy instantaneously but get affected by the temperature.
The lead acid battery is a motorcycle battery of 12 volts and has six cells made up of plastic. Each cell has positive and negative plates immersed in a solution of dilute sulphuric acid which is the electrolyte here. The six cells are connected to provide a fully charged battery. The battery makes use of an electrochemical reaction which converts chemical energy into electrical energy by losing electrolytes when dissolved in sulphuric acid.
Each cell has plates made up of lead calcium or lead antimony. A paste is an active material here which is bonded to the plates. When there is an electrical circuit across the terminals of the battery in the active material, the chemical reaction with sulphuric acid occurs. We can represent this overall reaction as:
 \[Pb(s) + Pb{O_2}(s) + 2{H_2}S{O_4}(aq) \to 2PbS{O_4}(s) + 2{H_2}O(l)\]
In the discharged state of the battery, the positive and negative plates become lead sulphate. The electrolyte loses the dissolved sulphuric acid and only water is left behind. This process is driven by electron conduction that happens in the external circuit.

Hence, the correct option is (B).

Note:
Chemical energy is stored in the lead acid battery and gets converted to electrical. This is known as battery charging whereas when the electric power gets charged to chemical energy, we call it discharging. Sulphuric acid decomposes in this process and thus it has to be replaced.