Hydrogen, the simplest element, is composed of one proton and one electron. It makes up more than 90% of the composition of the universe. More than 30% of the mass of the sun is atomic hydrogen. It is the third most abundant element in the earth's surface, and is found mostly in water. Under ordinary conditions, hydrogen is a colorless, odorless, tasteless, and nonpoisonous gas composed of diatomic molecules (H2).
             When cars burn gasoline, they would ideally burn it perfectly and create nothing but carbon dioxide and water in their exhaust. Unfortunately, the internal combustion engine is not perfect. In the process of burning the gasoline, it also produces; Carbon monoxide, a poisonous gas , Nitrogen oxides, the main source of urban smog , unburned hydrocarbons, the main source of urban ozone . Catalytic converters eliminate much of this pollution, but they aren't perfect either. Air pollution from cars is a real problem in big cities.
             Carbon is also a problem. When Carbon burns, it turns into a lot of carbon dioxide gas. Gasoline is mostly carbon by weight, so a gallon of gas might release 5 to 6 pounds of carbon into the atmosphere. The U.S. is releasing roughly 2 billion pounds of carbon into the atmosphere each day. If it were solid carbon, it would be extremely noticeable, it would be like throwing a 5-pound bag of sugar out the window of your car for every gallon of gas burned
             (Knapp 1). But because the 5 pounds of carbon comes out as an invisible gas (carbon dioxide), most of us are oblivious to it. The carbon dioxide coming out of every car's tailpipe is a
             greenhouse gas. The ultimate effects are unknown, but it is a strong possibility that, eventually, there will be climate changes that affect everyone on the planet. For this reason, there are growing efforts to replace gasoline with hydrogen.
             There are two possible sources for the hydrogen. Electrolysis of water; Using electricity, it is easy ...