in which the electrodes are immersed. In either a wet or dry cell, sufficient liquid must be present to allow the chemical reactions to take place.Electricity is generated in cells because when any of these chemical substances is dissolved in water , its molecules break up and become electrically charged ions. Sulfuric acid is a good example. Sulfuric acid, H2SO4, has molecules of which consist of two atoms of hydrogen, one of sulfur and four oxygen. When dissolved in water, the molecules split into three parts, the two atoms of hydrogen separate and in the process each loses an electron, becoming a positively charged ion (H+). The sulfur atom and the four atoms of oxygen remain together as a sulfate group (SO4), and acquire the two electrons lost by the hydrogen atoms, thus becoming negatively charged (SO4--). These groups can combine with others of opposite charge to form other compounds.The lead-acid cell uses sulfuric acid as the electrolyte. The lead-acid storage battery is the most common secondary battery used today, and is typical of those used in automobiles. The following will describe both the charging and discharging phase of the lead-storage battery and how sulfuric acid, as the electrolyte, is used in the process. The lead storage battery consists of two electrodes or plates, which are made of lead and lead peroxide and are immersed in an electrolytic solution of sulfuric acid. The lead is the anode and the lead peroxide is the cathode. When the battery is used, both electrodes are converted to lead sulfate by the following process. At the sulfate ion that is present in the solution from the sulfuric acid. At the cathode, meanwhile, the lead peroxide accepts two electrons and releases the oxygen; lead oxide is formed first, and then lead joins the sulfate ion to form lead sulfate. At the same time, four hydrogen ions released from the acid join the oxygen released from the lead peroxide to form water. When all the sulfuri...
