Final answer:
In a car battery, the oxidation reaction at the cathode produces lead sulfate (PbSO₄). These batteries can produce a 12-V output by arranging six cells in series and are rechargeable. They are commonly used for their reliability, but must be disposed of properly due to their hazardous materials.
Step-by-step explanation:
The product of the oxidation reaction that occurs at the cathode of a car battery during the discharge process is lead sulfate (PbSO₄). In a lead-acid battery, the cathode reaction involves lead dioxide (PbO₂), hydrogen ions (H+), and sulfate ions (HSO₄⁻) reacting to produce PbSO₄ and water (H₂O). Each cell in such a battery produces 2 volts (V), and six cells are typically connected in series to create a standard 12-V car battery. A car battery is rechargeable, meaning it can be recharged by reversing the chemical reactions that occur during discharge. However, over time, the efficiency of this recharge diminishes due to lead sulfate falling off the electrodes, which prevents the battery from lasting indefinitely.
During the discharge of a lead-acid battery, the overall cell reaction can be represented as follows:
- Anode: Pb(s) + HSO₄⁻(aq) → PbSO₄(s) + 2e⁻ + 2H+(aq)
- Cathode: PbO₂(s) + HSO₄⁻(aq) + 3H+(aq) + 2e⁻ → PbSO₄(s) + 2H₂O(l)
While the car battery is capable of high current density and is commonly used because of its reliability and power output, it also is made of lead and contains a caustic electrolyte in the form of sulfuric acid, which requires proper disposal.