The reaction change the water-gas or reaction shifts, water-gas, (WGSR) is a chemical reaction in which carbon monoxide reacts with steam, water, producing carbon dioxide and hydrogen gas does. The importance of this reaction is that from two inexpensive and abundant substances ( and2 2o), hydrogen gas can be produced, which has many industrial applications. The reaction was first discovered by Italian scientist Felice Fontana in 1780. Before the early 20th century, hydrogen by reacting steam under high pressure with iron and the production of iron, iron oxide and hydrogen is obtained, respectively.