In the large scale, hydrogen is produced currently by steam reforming of hydrocarbons. Steam and methane reacts with each other in the presence of nickel catalyst at 35 atm and at a temperature of 800°C gives hydrogen.
CH4(g) + H2O(g) → CO(g) + 3H2(g)
Steam is passed over a red hot coke to produce carbon monoxide and hydrogen.
Water is reduced to hydrogen with carbon monoxide by passing over iron oxide catalyst at 400°C
CO(g) + H2O(g) → CO2(g) + H2(g)
Hydrogen is produced as a by-product in oil refining industry during the cracking of long chain hydrocarbons.
Hydrogen is also obtained in the manufacture of chlonne and sodium hydroxide via electrolysis of a concentrated solution of sodium chloride