HYDROGEN — H2

Hydrogen is an important commercial chemical. It is prepared industrially by two processes: the “water gas reaction ” using coke and water (equation 1), and the steam reforming process using natural gas and water (equation 2). Both reactions require high temperatures. C(s) + H2O(g) xxv CO(g) + H2(g) (1) CH4(g) + H2O(g) xxv CO(g) + 3 H2(g) (2) The mixture of products from these two reactions is often called synthesis gas or syngas. The carbon monoxide in this gaseous mixture can be made to react with more water in the “water gas shift reaction ” (equation 3) to produce hydrogen and CO2. CO(g) + H2O(g) xxv CO2(g) + H2(g) (3) The CO2 is then easily removed by passing this gas through a solution of sodium hydroxide. The carbon dioxide reacts and dissolves (equation 4), leaving pure hydrogen. CO2(g) + 2 OHG(aq) xxv CO32G(aq) + H2O(l) (4) A subject of much current interest in chemistry is the conversion of synthesis gas (CO + H2) to other products such as methanol (equation 5) and liquid hydrocarbons (equation 6). These substances could be used as synthetic fuels, such as substitutes for gasoline