Hydrogen - Types and Colour for JEE

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Hydrogen at a Glance

The lightest and smallest element in the periodic table is hydrogen. Hydrogen is a gas composed of diatomic molecules with the formula under normal conditions. Hydrogen gas is colourless, odourless, tasteless, non-toxic and extremely flammable. For a cleaner alternative fuel choice, hydrogen is one of the most abundant substances on the planet. Hydrogen fuel is an oxygen-burned, zero-emission fuel. It can be utilised in both internal combustion engines and fuel cells. It's also employed as a propulsion fuel for spaceships.

Types of Hydrogen

Different colours of hydrogen are attributed to it depending on the kind of production. Green hydrogen, blue hydrogen, brown hydrogen, yellow hydrogen, turquoise hydrogen and even pink hydrogen are all examples of hydrogen. They are simply colour codes or nicknames used in the energy industry to distinguish between hydrogen kinds. The kind of hydrogen is determined by the process by which it is created.

Black Hydrogen

Coal produces black hydrogen, often known as brown hydrogen. The black and brown colours represent bituminous (black) and lignite (brown) coals. Coal gasification is a method for producing hydrogen. The majority of hydrogen produced in the United States today is "brown." It is produced using steam-methane reformation, which uses steam to create hydrogen from a methane source such as natural gas. While both of these methods create clean, zero-emission hydrogen fuel, they also emit considerable volumes of greenhouse gas emitting CO2, which makes them less-than-ideal options for genuinely pure hydrogen.

Blue Hydrogen

Blue hydrogen is identical to grey hydrogen, except that it uses carbon capture and storage to sequester (store) the majority of emissions (CCS). Blue hydrogen is a low-carbon fuel because it captures and stores carbon dioxide rather than releasing it into the atmosphere. Steam methane reforming and coal gasification, both with carbon capture and storage are the two main production processes.

Although blue hydrogen is a cleaner option than grey hydrogen, it is more expensive due to the need for carbon capture technologies. This is why blue hydrogen is frequently referred to as a carbon-neutral energy source, even though "low carbon" would be a more true description because approximately 10-20% of the CO2 produced cannot be absorbed.

Green Hydrogen

Hydrogen created by electrolysis dividing water is known as green hydrogen. Only hydrogen and oxygen are produced without harming the environment. We need electricity and power to achieve electrolysis. Renewable energy sources, such as wind or solar, are used to fuel this green hydrogen production process. As a result, green hydrogen is the most environmentally friendly option. Hydrogen is produced from renewable energy sources with no CO2 emissions as a by-product. Green hydrogen technology, on the other hand, is now prohibitively expensive to execute, and, thus, accounts for only a small portion of global hydrogen energy production.

Grey Hydrogen

Grey hydrogen is made from natural gas, and the resulting emissions are released into the atmosphere. It is usually made of different types of gases, for example, methane, which is split into steam (the primary cause of global warming) and hydrogen. Grey hydrogen production from coal is increasing, resulting in much higher emissions per unit of hydrogen produced, to the point where it is often commonly referred to as brown or black hydrogen instead of grey hydrogen. Grey hydrogen isn't a viable option in the long run as it is a climate destroyer.

Pink Hydrogen

This is created by electrolyzing water with electricity provided by a nuclear power station. Purple hydrogen and crimson hydrogen are two names for nuclear-produced hydrogen. Furthermore, the extremely high temperatures produced by nuclear reactors might be utilised to produce steam for more efficient electrolysis or steam methane reforming using fossil gas.

Green Hydrogen Uses

Green hydrogen is emerging as a critical factor in achieving energy transition and securing a long-term future. The lower cost of manufacturing green hydrogen from renewable energy sources and the need to cut carbon emissions have given clean hydrogen a huge boost.

In terms of transportation, green hydrogen can be used in railways, huge ships, buses, trucks and other vehicles for long-distance mobilizations for either urban freight movement within cities and states or for people. Green hydrogen, which is created using electrolysis (a high-energy process) and renewable energy sources, is a costly option that accounts for just around 5% of overall generation.

The demand for fossil fuels is so great that it is estimated that the world will run out of fossil fuels before the middle of the twenty-first century. As a result, the advancement of alternate energy sources is critical. Nuclear energy is one of the most widely used alternative energy sources today. However, it can only be utilised to generate electrical energy, and electrical energy accounts for only 20% of the total energy required. The use of hydrogen as a fuel is important to save our environment.

Hydrogen provides several advantages over other alternatives. It is abundantly available, for example. It produces no pollution because its combustion product is water. Liquid hydrogen, for example, is utilised as rocket fuel. Instead of damaging carbon dioxide, sulphur dioxide, hydrocarbons, and other nitrogen oxides, this fuel produces water.


Hydrogen has many types depending upon its production. A hydrogen is a form of energy that must be created from a different component. Hydrogen can be created (separated) from a variety of sources, such as water, fossil fuels, or biomass, and used as an energy or fuel source.

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FAQs on Hydrogen - Types and Colour for JEE

1. What are the disadvantages of hydrogen fuel cells?

Despite the many benefits of hydrogen fuel cells, there are a few drawbacks and hurdles to overcome:

  • Hydrogen Extraction: While hydrogen is the most abundant element in the universe, it does not exist in its natural state and must be extracted from water or separated from carbon-based fossil fuels. Both of these procedures need a significant quantity of energy.

  • Cost of Raw Materials: Fuel cells and some types of water electrolyzers require precious metals such as platinum and iridium as catalysts, which means the initial cost of fuel cells (and electrolyzers) can be considerable. 

  • Highly Flammable: Hydrogen is a highly combustible fuel, thus safety concerns are warranted.

2. Write a short note on the history of hydrogen?

Hydrogen's origins can be traced back to the Greek words 'hydro', which means water, and ‘Gennaro’, which means manufacture. In a nutshell, this means "water producer." Cavendish discovered and isolated hydrogen in 1766, at a time when hydrogen was thought to be many distinct things. Cavendish, who discovered the element, mistook it for inflammable air made from metals, but it turned out to be proof of the synthesis of hydrogen by the action of acids on metals. Before this, both Robert Boyle and Paracelsus had employed iron and acids to create hydrogen gas, and Antoine Lavoisier named hydrogen after it used to produce water when ignited in the air.