Octane Formula

Octane Formula

Octane comes under hydrocarbons and consists of carbon and hydrogen atoms. The Octane Formula is C8H18. Petroleum contains the majority of the hydrocarbon groupings. Octane has a variety of structural isomers, although they vary according to the number and placement of carbon chain branches. Edwin L. Drake discovered it in August 1859.

What is Octane?

It is a chemical substance that can be found in gasoline or petrol and is used to gauge the quality of fuel. It is a white liquid with a gasoline-like odour that is volatile and very combustible. Its ratings are based on a fuel’s ability to prevent knocking, which happens when fuel ignites permanently in an engine cylinder, reducing efficiency and possibly damaging the engine. The fuels contain an oxygenate, also known as octane, that prevents knocking by oxygenating the fuel.

Octane Structural Formula

Its molar mass is 114.23 g/mol. It has a 125.6 °C boiling point. Octane’s melting point is -57 °C. It has a 703 kg/m3 density. It is a colourless liquid that is quite combustible. Furthermore, it is an odourless liquid with a gasoline scent. To distinguish it from refined oil, crude oil is one of the many forms of hydrocarbons that can be found in nature. The most significant commercially, however, is natural gas, which is a lighter fraction of hydrocarbons that can be free or dissolved asphalt, tar, or pitch, which are solid or semi-solid forms of hydrocarbons.

The 18 Isomers of octane are:

All isomers of octane are listed below-


3-Methylheptane (2 enantiomers)




2,3-Dimethylhexane (2 enantiomers)

2,4-Dimethylhexane (2 enantiomers)



3,4-Dimethylhexane (2 enantiomers + 1 meso compound)



2,2,3-Trimethylpentane (2 enantiomers)

2,2,4-Trimethylpentane (isooctane)




What is the Formula of Octane?

C8H18 is the Octane Formula. A major commercial form of hydrocarbons is natural gas, which is a lighter fraction of hydrocarbons that can be free or dissolved asphalt, tar, or pitch, which is a solid or semi-solid form of hydrocarbons. Hydrocarbons are found in nature in a variety of forms but are most commonly found as liquid petroleum, which is known as crude oil to distinguish it from refined oil.


Octane is used as a solvent. It is a raw material for chemicals. As a chemical agent, it plays a crucial role in the petroleum industry. It is an ingredient in gasoline. The octane rating is used to assess the fuel’s quality.

Solved Examples

To solve examples related to Octane Formula, it is necessary to revise it from time to time. All the questions asked on the basis of the Octane Formula can be solved with the help of Extramarks. Consistent revision of questions will help students to retain the Octane Formula for a longer period of time. Students can get help from Extramarks to learn all the chemistry topics in detail. They can also make use of the study resources of Extramarks to prepare effectively for their upcoming examinations.

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FAQs (Frequently Asked Questions)

1. What is the exact Octane Formula?

The Octane Formula is represented by C8H18. The Octane Formula is crucial for understanding the structure of octane and all the chemical reactions involving it. It is also necessary to learn the properties of octane and its uses. 

2. What are the various uses of octane?

Octane has a wide range of applications. Octane is used in industries as a solvent. It is one of the important chemicals in the petroleum industry. It is an ingredient in gasoline.