Question

Draw neat and labelled diagram of lead accumulator.

Hint:

Remember that during charging, the reactions are reversed, and the cell acts as an electrolytic cell. During discharging, it acts as a galvanic cell.

Answer 1

Step 1: Understanding the Concept:
A lead accumulator (lead-acid battery) is a secondary electrochemical cell, meaning it can be recharged by passing an external electric current through it.
Step 2: Detailed Explanation:
A standard diagram involves the following components:
1. Anode: A grid of lead packed with finely divided spongy lead (\( Pb \)).
2. Cathode: A grid of lead packed with lead dioxide (\( PbO_2 \)).
3. Electrolyte: Aqueous solution of sulfuric acid (\( H_2SO_4 \)) with a density of \( 1.28 \, g/mL \) (approx 38% by mass).
4. Container: Usually made of hard rubber or plastic.
During discharge, both electrodes are converted to lead sulfate (\( PbSO_4 \)).
Cell Representation:
\( Pb(s) | PbSO_4(s) | H_2SO_4(aq) | PbSO_4(s) | PbO_2(s) | Pb(grid) \)
Step 3: Final Answer:
The lead accumulator uses \( Pb \) as anode, \( PbO_2 \) as cathode, and \( H_2SO_4 \) as electrolyte.