It is noticed that during discharging the following does not happen

The correct answer is D. The cell absorbs energy.

During discharging, the following happens:

• Both anode and cathode become PbSO4.
• Specific gravity of H2SO4 decreases.
• Voltage of the cell decreases.

The cell does not absorb energy. In fact, it releases energy. This energy is used to power devices such as flashlights and cars.

Here is a more detailed explanation of each option:

• Option A: Both anode and cathode become PbSO4. This is true. During discharging, the lead (Pb) anode and the lead dioxide (PbO2) cathode react with sulfuric acid (H2SO4) to form lead sulfate (PbSO4).
• Option B: Specific gravity of H2SO4 decreases. This is also true. As the H2SO4 is used up during discharging, the specific gravity of the solution decreases.
• Option C: Voltage of the cell decreases. This is also true. As the H2SO4 is used up during discharging, the voltage of the cell decreases.
• Option D: The cell absorbs energy. This is false. In fact, the cell releases energy. This energy is used to power devices such as flashlights and cars.