An example of a non-rechargeable cell is

Step 1: Analyze the question The question asks which cell is a non-rechargeable cell, i.e. a primary cell. Once its chemicals are used up, it cannot be restored by passing current back through it.

Step 2: Explain the concept

• Primary cells have irreversible chemical reactions, so they cannot be recharged. Examples: the dry Leclanché cell, the simple voltaic cell, and the mercury cell.
• Secondary cells have reversible chemical reactions, so they can be recharged by passing current through them in the opposite direction. Examples: the lead-acid accumulator, the nickel-iron (Edison) cell, and the nickel-cadmium cell.

Step 3: Check each option

• A. Nickel iron: This is the Edison accumulator, a secondary cell, so it is rechargeable.
• B. Mercury cadmium: This one is tricky. It is not a standard named cell. Mercury cells (zinc-mercuric oxide) are primary, and nickel-cadmium cells are secondary. "Mercury cadmium" is not a recognised common cell type, so it is not the intended answer.
• C. Dry Leclanché: This is the common zinc-carbon dry cell with a zinc case, a carbon rod, and an ammonium chloride paste. It is a primary cell, so it is non-rechargeable.
• D. Lead-acid: This is the car battery accumulator, a secondary cell, so it is rechargeable.

Step 4: Answer The dry Leclanché cell is the standard textbook example of a non-rechargeable (primary) cell.

Exam tip: Remember that "accumulator" means rechargeable. Lead-acid and nickel-iron are both accumulators. Dry cells, like the ones in your torch and radio, are primary cells and cannot be recharged.