Hydrogen was discovered from water in 1766 by Henry Cavendish. Its name hydrogenium comes from Greek words hydór = water a gennaó = form. That element has the symbol H and an atomic number of 1. Under ordinary conditions hydrogen is a colorless, odorless, tasteless gas that is only slightly soluble in water; it is the least dense and lightest gas known. It is the first element in Group 1 of the periodic table. Ordinary hydrogen gas is made up of diatomic molecules (H2) that react with oxygen to form water (H2O) and hydrogen peroxide (H2O2), usually as a result of combustion. A jet of hydrogen burns in air with a very hot blue flame. The flame produced by a mixture of oxygen and hydrogen gases (as in the oxyhydrogen blowpipe) is extremely hot and is used in welding and to melt quartz and certain glasses. Hydrogen gas must be used with caution because it is highly flammable; it forms easily ignited explosive mixtures with oxygen or with air (because of the oxygen in the air). At high temperatures hydrogen is a chemically active mixture of monohydrogen (atomic hydrogen) and the normal diatomic hydrogen.
Hydrogen has a great affinity for oxygen and is a powerful reducing agent- It reacts with nitrogen to form ammonia. With the halogens it forms compounds (hydrogen halides) that are strongly acidic in water solution. With sulfur it forms hydrogen sulfide (H2S), a colorless gas with an odor like rotten eggs; with sulfur and oxygen it forms sulfuric acid. It combines with several metals to form metal hydrides such as calcium hydride. Combined with carbon (and usually other elements) it is a constituent of a great many organic compounds, such as hydrocarbons, carbohydrates, fats, oils, proteins, and organic acids and bases.
Hydrogen has three common isotopes. The simplest isotope, called protium, is just ordinary hydrogen. The second, a stable isotope called deuterium, was discovered in 1932. The third isotope, tritium, was discovered in 1934.
While hydrogen is only about one part per million in the atmosphere, it is the most abundant element in the universe. It is believed that hydrogen makes up about three quarters of the mass of the universe, or over 90% of the molecules. It is found in the sun and in other stars, where it is the major fuel in the fusion reactions from which stars derive their energy. Hydrogen is prepared commercially by catalytic reaction of steam with hydrocarbons, by the reaction of steam with hot coke (carbon), by the electrolysis of water, and by the reaction of mineral acids on metals.
Hydrogen is used extensively today to make ammonia, methanol, gasoline, heating oil, and rocket fuel. It is also used to make fertilizers, glass, refined metals, vitamins, cosmetics, semiconductor circuits, soaps, lubricants, cleaners, and even margarine and peanut butter.
It is transported in bottles made of steel under high pressure, which are labeled with red colour for safety precautions. Also we can transport it with using conduits.
In chemical industry, hydrogen is used for production important chemicals, e.g: HCL (hydrochloric acid), NH3 (ammonia). Also it is used in production of syntethic gasoline from coal. Hydrogen is the least dense element of periodic table. Because of his denstiy, it was used as a filling of balloons and airships.
Hydrogen is important in mechanical industry. Its flame can cut and weld metals or steel plates.
Hydrogen is a very ecological form of enrgy. On our planet there are unfailing sources of that element in water. After the combustion it makes the water again. It could replace petrol, oil, coal, and maybe electrity. It´s a big vision to get reserve source of energie for the people.