Final answer:
During the recharging of a lead-acid battery, hydrogen and oxygen gases are produced from the decomposition of water in the sulfuric acid electrolyte, which can be potentially explosive and dislodge particles from the plates, requiring careful monitoring of the charging process.
Step-by-step explanation:
When discussing the gases involved in charging the lead-acid battery, we focus on the chemical reactions that occur during the recharging process. The anodes in a lead-acid battery are composed of lead, and the cathodes consist of lead dioxide (PbO₂), all of which are immersed in an aqueous solution of sulfuric acid. During charging, water (H₂O) in the electrolyte solution undergoes decomposition, leading to the evolution of hydrogen (H₂) gas and oxygen (O₂) gas according to the reaction:
2H₂O(l) → 2H₂(g) + O₂(g)
This reaction can lead to the production of explosive hydrogen gas. It also has the potential to dislodge particles of lead sulfate (PbSO₄) or lead dioxide from the plates, which can accumulate at the bottom of the battery cell, causing a short circuit. Therefore, the recharging process must be carefully managed to prevent these risks and maximize the battery's lifespan. With appropriate maintenance, a lead-acid battery has the capability to be discharged and recharged thousands of times, making it a reliable power source in vehicles and other applications.