How does Sulphuric acid work???

Question

How does it work in car batteries, surface and metal cleaners, etc. (write the easiest/simplest answer to one example of the above or any other COMMON example)

Answer 1

Sulphuric acid is a strong acid, that means it has a great tendency to oxidise elements and compounds to form salts. In a car battery, sulfuric acid reacts with the lead oxide so it forms soluble lead sulphate while generating electrons (Electricity). As a cleaner, also reacts with several organic compounds (Destroying them) and solubilizing oxides to form salts, but it is not very recommendable for other reasons, leaves the metal surfaces without the naturally protective layer (Surface activation). Rust is iron oxide, diluted sulphuric acid will solubilize it in the form of iron sulphate, but it really is not a very good way to remove rust.

Answer 2

Basically, when a battery is being discharged, the sulfuric acid in the electrolyte is being depleted so that the electrolyte more closely resembles water. At the same time, sulfate from the acid is coating the plates and reducing the surface area over which the chemical reaction can take place. Charging reverses the process, driving the sulfate back into the acid.
The electrolyte (sulfuric acid and water) contains charged ions of sulfate and hydrogen. The sulfate ions are negatively charged, and the hydrogen ions have a positive charge. Here's what happens when you turn on a load (headlight, starter, etc). The sulfate ions move to the negative plates and give up their negative charge. The remaining sulfate combines with the active material on the plates to form lead sulfate. This reduces the strength of the electrolyte, and the sulfate on the plates acts as an electrical insulator. The excess electrons flow out the negative side of the battery, through the electrical device, and back to the positive side of the battery. At the positive battery terminal, the electrons rush back in and are accepted by the positive plates. The oxygen in the active material (lead dioxide) reacts with the hydrogen ions to form water, and the lead reacts with the sulfuric acid to form lead sulfate.
The ions moving around in the electrolyte are what create the current flow, but as the cell becomes discharged, the number of ions in the electrolyte decreases and the area of active material available to accept them also decreases because it's becoming coated with sulfate.
http://www.batterystuff.com/tutorial_battery_made.html