Familiarize yourself with hydrogen

Hydrogen is the simplest and most abundant element in the universe. It accounts for about 75 % w/w of its normal matter. Hydrogen is a major component of water, oil, natural gas, almost all organic compounds, and biomass.

and all living matter. Despite its simplicity and abundance, hydrogen occurs seldom on Earth, as a gas, being mostly combined with other elements. It can be produced from oil, natural gas, and biomass, or by splitting water with renewable solar or electric energy. Hydrogen is an energy carrier used to move, store, and transport energy produced from other sources.

Hydrogen, the element with atoms consisting of one proton and one electron, forms the simplest and lightest diatomic gas. On Earth it is found mainly in bound state, especially as water. The first element of the periodic table was discovered by Henry Cavendish nearly 250 years ago. It is colorless, odorless, highly flammable, and a very good heat conductor. As compared to normal air, the density of hydrogen is approximately 14.5 times smaller and has a very significant diffusivity, i.e., it mixes very well and quickly with other gases.


Hydrogen can be produced by the electrolytic decomposition of water, which produces oxygen and hydrogen. When used as a fuel, the end-product of the combustion of hydrogen is water, which is thus recycled. It can also be extracted industrially from natural gas by steam reforming, or produced from methanol, ethanol, or biomass.

Its properties are favorable in many respects – hydrogen is nontoxic, noncorrosive, not carcinogenic, does not produce greenhouse effect, non-radioactive if released accidentally, does not cause any permanent pollution, and has one of the highest known calorific values. Therefore, thousands of scientists and engineers work worldwide to exploit its potential.

Hydrogen can be used as an energy source and fuel in countless areas and may play a dominant role in energy distribution in the future.

Hydrogen has been used for nearly 250 years, being widely used in the chemical industry for about 100 years. Nearly 80 million tons of hydrogen are currently produced in the world every year, and there are several industrial hydrogen production facilities in Hungary, e.g., in Százhalombatta, Kazincbarcika, and Budapest. It is typically used in ammonia production, oil refining, and many other industries. Industrial gas companies also produce hydrogen as a routine operation, albeit in significantly smaller amounts.

A traditional way to produce hydrogen in the laboratory, often used as a school experiment, is to pour hydrochloric acid onto zinc. Hydrogen gas is then evolved to form zinc chloride:

Zn (s) + 2 HCl (aq.) = ZnCl2 (aq.) + H2 (g),

where: s – solid, aq. – aqueous solution, g – gas.

It may be well known to react Alkali metals, such as sodium or potassium react with water. In this case, hydrogen gas is produced in a violent reaction:

2 Na (s) + 2 H2O (l) = 2 NaOH (aq.) + H2 (g)

where: l – liquid.

The above reactions are not used to produce large amounts of hydrogen on an industrial scale. Hydrogen is present in many compounds, so in principle it can be produced by a wide variety of techniques, but in current practice, production from fossil fuels is the absolute dominant method. Within this, the production of hydrogen from natural gas, more precisely from methane (CH4), is decisive. The latter method is also called steam reforming, SMR (Steam Methane Reforming):

CH4 (g) + H20 (g) = CO (g) + 3 H2 (g)