Final answer:
The acid used in automobile batteries is sulfuric acid. It acts as the electrolyte and facilitates the flow of electrons. When sulfuric acid reacts with lead plates, it produces electric current.
Step-by-step explanation:
The acid used in automobile batteries is sulfuric acid. This acid acts as the electrolyte in the battery, facilitating the flow of electrons between the electrodes. In a lead-acid battery, the sulfuric acid reacts with lead plates to produce electric current.