Question

Which of the following is a secondary cell?

• A. Leclanche cell
• B. Lead storage battery
• C. Concentration cell
• D. All of these

Hint:

Remember:
• Dry cell \( \rightarrow \) Primary cell
• Lead-acid battery \( \rightarrow \) Secondary cell Secondary cells are rechargeable because their reactions are reversible.

Answer 1

The Correct Option is B

Concept: Electrochemical cells are classified into:
• Primary cells — cannot be recharged once discharged.
• Secondary cells — rechargeable cells in which chemical reactions are reversible. Secondary cells can be used repeatedly by passing electric current through them after discharge.

Step 1: Analyzing Leclanche cell.
Leclanche cell is a dry cell commonly used in torches and clocks. The chemical reactions occurring in it are irreversible. Hence, it is a: \[ Primary cell \] Therefore, it is not a secondary cell.

Step 2: Analyzing Lead storage battery.
Lead storage battery is rechargeable. During charging, the discharge reaction gets reversed by supplying electrical energy. Thus, it is a: \[ Secondary cell \]

Step 3: Analyzing Concentration cell.
A concentration cell is a galvanic cell based on concentration difference between two electrodes or electrolytes. It is not classified as a secondary rechargeable battery. Therefore, it is not a secondary cell.

Step 4: Conclusion.
Only lead storage battery is a rechargeable electrochemical cell. Hence, the correct answer is: \[ Lead storage battery \]