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Given below are statements regarding the operation of a lead storage battery: A. The density of the sulphuric acid solution decreases during the discharging of the battery. B. The pH of the electrolyte decreases during the discharging of the battery. C. During charging, the oxidation state of lead at the positive plate changes from +2 to +4 . D. During charging, water is produced at the anode. Choose the correct answ

Options

  1. AA and C only
  2. BA, B and C only
  3. CB and D only
  4. DC and D only

Correct answer

A. A and C only

Step-by-step solution

Statement A is correct: During discharging, sulphuric acid is consumed and water is produced according to the overall reaction Pb + PbO ₂ + 2 H ₂ SO ₄ 2 PbSO ₄ + 2 H ₂ O . This leads to a decrease in the density of the electrolyte. Statement B is incorrect: Since H ₂ SO ₄ (and thus H ^+ ions) is consumed during discharging, the concentration of H ^+ decreases, which means the pH of the electrolyte increases. Statement C is correct: During charging, the positive plate acts as the anode where oxidation occurs. PbSO ₄

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