The cell reaction when a car battery releases energy is given by the equation below - VCE - SSCE Chemistry - Question 8 - 2003 - Paper 1
Question 8
The cell reaction when a car battery releases energy is given by the equation below.
$$\text{Pb(s)} + \text{PbO}_2(s) + 4\text{H}^+(aq) + 2\text{SO}_4^{2-}(aq) \rig... show full transcript
Worked Solution & Example Answer:The cell reaction when a car battery releases energy is given by the equation below - VCE - SSCE Chemistry - Question 8 - 2003 - Paper 1
Step 1
A. Pb(s) + SO₄²⁻(aq) → PbSO₄(s) + 2e⁻
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Answer
This reaction shows the conversion of lead and sulfate ions into lead sulfate along with the release of electrons. While this could occur, it's not the process happening at the negative electrode during recharge.
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Answer
This equation describes a reduction process, but it does not represent the correct reaction at the negative electrode.
Step 3
C. PbSO₄(s) + 2e⁻ → Pb(s) + 4H⁺(aq) + SO₄²⁻(aq)
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Answer
This is the correct equation for the reaction occurring at the negative electrode when the battery is being recharged. It shows lead sulfate being converted back to lead, while releasing sulfate ions and protons.
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Answer
This equation is incorrect as it does not represent the correct charge process happening during battery recharging; it incorrectly implies that water is being consumed in the reaction.
