Hydrogen Gas Formula

Define Hydrogen Gas Formula

One of the simplest formulas used in chemistry is the hydrogen gas formula. The first element mentioned in the periodic table is hydrogen. The properties that describe hydrogen gas are odourless, colourless, tasteless, non-metallic and highly combustible gas. It is the most abundant element found in the universe, especially in giant gas planets and stars. Being one of the smallest chemical elements, it comprises only one proton in the nucleus. It was during the 16th century, hydrogen gas for the first time was manufactured using metals and acids. 

Properties of Hydrogen Gas

Chemical properties

  • Its formula is H2

  • It has 3 known isotopes. 

  • The force of attraction amongst its molecules is incredibly weak, as a result of which, the melting and boiling points of this element are very low. Its melting point is -259.20C and its boiling point is -252.90C. 

  • Its density is 0.0893 g/L.

  • Its molecular weight is 2.016 g/mol. 

Other properties 

  • It tends to diffuse faster than any other gas because the velocity of the molecules of hydrogen gas is higher than that of any other gas at a given temperature. 

  • Hydrogen is visible in transparent, infrared, and ultraviolet light (but only to wavelengths below 1800 Å). 

  • Its molecule is considered to be the simplest of all. It consists of two protons and electrons which are held together by electrostatic forces. 

Uses of Hydrogen Gas 

There are a number of different uses pertaining to hydrogen gas. They are as follows:

  • One of the major uses of hydrogen gas for energy is rocket fuel. In fact, liquid hydrogen had been started to be used as rocket fuel from the 1950s by NASA and it was them who had first made use of hydrogen fuel cells for powering the electrical systems on their spacecraft. 

  • When it comes to the process of breaking crude oil into gasoline, fuel oils, etc., hydrogen plays an important role in it. 

  • Equal volumes of hydrogen gas, as well as helium, are filled into weather observation balloons. 

  • Hydrogen is also popular as a transportation fuel. It is used in fuel cell electric vehicles and is considered to be highly efficient. It is also used in combustion engines. 

  • When hydrogen atoms are combined with oxygen atoms, hydrogen fuel cells help to produce electricity. 

  • The process of hydrogenation wherein vegetable oils that are edible are transformed into vanaspati oils, also makes use of hydrogen. 

The Process of Production of Hydrogen 

Hydrogen can be prepared in various ways, and we have listed two crucial methods below. 

By passing an electric current through the water there is a split in hydrogen and oxygen molecules. This is known as electrolysis.

When natural gas is reacted with steam at a very high temperature the resultant mixture is hydrogen gas, carbon dioxide, and carbon monoxide. 

Chemical Formulas Using Hydrogen 

Here’s a list of important chemical formulas that include hydrogen to form a compound. 

  • Hydrogen sulphate formula- HO4S-

  • Hydrogen sulphide formula- H2S

  • Hydrogen iodide formula- HI

  • Hydrogen bromide formula- HBr

  • Hydrogen cyanide formula- HCN


When the energy that is greater than the dissociation energy or equal to it is supplied, then one molecule of hydrogen will dissociate into two atoms. 

\[ H_{2} \rightarrow {2H} \]

Atomic hydrogen is known to be very reactive. It combines with most of the elements and forms hydrides along with reducing metallic oxides. And this reaction ends up producing the particular metal in its elemental state. 

At room temperature, the reaction rates of molecular hydrogen are very low, almost negligible. But it can still react with various compounds and elements because when the temperature is increased, its reaction rates also increase. 


Hydrogen has been recognized as a vital element that is used in the clean-burning of fuel. It is a non-metallic component that comes with a molecular formula of H2

Hydrogen as a gas is non-carcinogenic and non-toxic in nature. It can be stored as a compressed gas or liquid that is reliable for internal combustion in vehicles.

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FAQs (Frequently Asked Questions)

1. Are there any drawbacks with association to hydrogen gas? If yes, then what are they? 

There are some disadvantages when it comes to hydrogen gas. These are as follows: 

  • The density of this gas is very low which makes it a compulsion for it to be compressed into a liquid state and then be stored at low temperatures. This makes the storage-related issues with this gas a little complicated. In fact, it is most of the time transported in small quantities only to avoid any sort of complications. 

  • Hydrogen energy is quite expensive. 

  • It is not enough to sustain the world’s population because even though it is available in abundance, the cost of harnessing hydrogen energy tends to limit extensive utilisation. 

  • The hydrogen gas used in fuel cells is extremely flammable. So, if it isn’t handled with utter caution and care, it can lead to fires and explosions. 

2. How do plants utilise hydrogen gas in the air?

When hydrogen gas and oxygen are split, the result is hydrogen, i.e., water, which is in turn used by plants for the process of photosynthesis. Plants combine hydrogen with carbon during that process, as a result of which, oxygen is released into the air. And that oxygen from the atmosphere is then utilised by all the living beings to survive. 

3. Is hydrogen gas safe for the environment? 

Yes, hydrogen gas is considered to be safe and non-toxic, unlike other conventional fuels. It is an environmentally friendly gas as it does not produce the amount of waste that fossil fuels tend to produce when they are burned. Its byproducts are simply water and heat. And neither do hydrogen fuel cells lead to the production of any kind of greenhouse gases. 

4. What colour is the flame of hydrogen?

When burned, hydrogen tends to produce a pale blue flame which is almost invisible if you try to look at it in broad daylight. But if there are any sort of impurities like dust, sodium, etc., in the air, then the flame might look yellowish. However, a hydrogen flame will never produce any kind of smoke if it is pure. You can study more about Hydrogen gas by referring to different study materials available on the Vedantu website and app which will help you to understand this topic better.

5. Explain the hydrogen sulphide formula. 

In a laboratory, when sulphide is treated with some standard acids it results in the formation of a weak acid known as H2S along with other salts and metals. H2S chemical name is hydrogen sulphide, a gas that is commonly found in the drilling and production of crude oil and natural gas. It is also found in wastewater treatment facilities and sewers. Its presence can be detected with its strong rotten egg smell. Moreover, the gas is colourless, highly flammable, corrosive, and toxic in nature.  

The standard laboratory preparation of hydrogen sulphide formula involves the use of ferrous sulphide to produce H2S:

\[FeS + 2 HCl \rightarrow FeCl_{2} + H_{2}S \]

Thioacetamide is also used to generate H2S in quantitative inorganic analysis. 

\[CH_{3}(S)NH_{2} + H_{2}O \rightarrow CH_{3} C(O)NH_{2} + H_{2}S\]

6. State the Chemical Structure of Hydrogen Formula?

In a hydrogen formula, the gas mainly consists of hydrogen atoms that form diatomic molecules. The molecular formula of hydrogen gas can be established by observing the hydrogen atoms. Typically, a pair of hydrogen atoms are seen to be bonded together into molecules. As a result, the formula is written and expressed as H2.







Molecular weight of hydrogen


Boiling Point


Melting Point


The structural representation of the hydrogen chemical formula is given below:

H -------- H

7. What are the Uses of Hydrogen Gas or H2?

There are several uses of hydrogen gas which are discussed below in detail for you. 

  • The flame produced from hydrogen and oxygen can produce a temperature of 28000C. This hydrogen-oxygen flame is implemented for the purpose of welding and cutting metals. 

  • Hydrogen is used in the hydrogenation process of the vegetable oils that transforms edible vegetable oils into vanaspati oils. 

  • Hydrogen gas has applications and uses in fuel cell electric vehicles and combustion engines. 

  • In weather observation balloons, an equal volume of helium and hydrogen gas is used for filling.

  • Hydrogen is also used in breaking crude oil into fuel oils and gasoline.