Question

When a lead storage battery is charge:
A.) $Pb{O_2}$ dissolves
B.) the lead electrode becomes coated with lead sulphate
C.) sulfuric acid is regenerated
D.) the amount of acid decreases

Answer 1

Hint: The lead storage batteries are used in automobiles such as in cars, trucks, buses, etc. In lead storage batteries, the anode is a group of lead plates and cathode is considered as lead dioxide. In lead storage cells the electrolyte is sulfuric acid.

Complete step by step answer:
The lead storage batteries are secondary batteries because they can be charged, discharged through a load and then again recharged. In the lead storage battery, the negative plate that is anode is made up of lead and positive plate that is cathode is made up of lead dioxide and these electrodes are dipped into an electrolyte solution of sulfuric acid. The lead storage batteries are useful because they can store a lot of charge and therefore, can provide high current for a short period of time. During the charging of lead storage batteries, it acts as an electrolytic cell and during the discharging of the lead storage battery, it acts as a galvanic cell.
During the charging of the lead storage battery, the reactions get reversed and the cathode becomes anode and anode becomes cathode. The charging of the lead storage battery is usually done by providing an external current source.
The reactions during charging that occurs at anode are:
$PbS{O_4}(s) + 2{e^ - } \to Pb(s) + SO_4^{2 - }(aq)$
The reactions during charging that occurs at cathode are:
$Pb{O_2}(s) + 2{H_2}O \to PbS{O_2}(s) + SO_4^{2 - }(aq)$
The overall reaction of charging can be written as:
$2PbS{O_4}(s) + 2{H_2}O(l) \to Pb(s) + Pb{O_2}(s) + 2{H_2}S{O_4}(aq)$
During the charging of the lead storage battery, concentration of hydrochloric acid (${H_2}S{O_4}$) increases because it is regenerated.

Hence, option C.) is the correct answer.

Note:
 Always remember that in the lead storage, the products obtained in the reaction at the cathode as well as the products obtained in the cathode reaction are insoluble. Due to which these products are readily available to participate in the reverse reaction that is the recharging of the cell.