Question

As a lead storage battery is charged.

• A. Lead dioxide dissolves
• B. Sulphuric acid is regenerated
• C. Lead electrode becomes coated with lead sulphate
• D. The concentration of sulphuric acid decreases

Answer 1

The correct option is B Sulphuric acid is regenerated

Net cell reaction during discharge:-

$P{b}_{\left(s\right)}+Pb{O}_{2\left(s\right)}+2H_{2}S{O}_{4\left(aq\right)}\to 2PbS{O}_{4\left(s\right)}+2H_2{O}_{\left(l\right)}$

$\to$ During discharge, $H_{2}S{O}_4$ is consumed and its density decreases.

$\to$ Fully charged cell gives a potential of about 2V. When the cell potential reduces to about 1.8V , it should be recharged.

Net cell reaction during recharge:-

$2PbS{O}_{4\left(s\right)}+2H_2{O}_{\left(l\right)}\to P{b}_{\left(s\right)}+Pb{O}_{2\left(s\right)}+2H_{2}S{O}_{4\left(aq\right)}$

$\to$ The concentration of $H_{2}S{O}_4$ increases as it is generated.