What type of electrolyte is contained in a lead-acid battery?

A lead-acid battery utilizes sulfuric acid as its electrolyte. In this type of battery, the sulfuric acid solution interacts with the lead and lead dioxide plates to facilitate the electrochemical reactions necessary for energy storage and release. When the battery discharges, lead sulfate forms on both the positive and negative plates, and when recharged, these compounds revert back to lead and lead dioxide while releasing sulfuric acid back into the solution.

The other options do not apply to lead-acid batteries. Acetic acid is typically found in vinegar and is not suitable for battery applications. Hydrochloric acid, while used in some industrial applications, does not participate in the chemical reactions of lead-acid batteries. Phosphoric acid is used in certain types of batteries, like lithium iron phosphate batteries, but not in traditional lead-acid batteries. The specific choice of sulfuric acid is critical, as its chemical properties enable efficient conduction of electric current and optimal performance during charge and discharge cycles in lead-acid batteries.