Aliphatic hydrocarbons are a class of organic compounds that consist exclusively of hydrogen and carbon atoms arranged in open chains or branched structures, rather than in aromatic rings. These hydrocarbons can be classified into two main groups: alkanes and alkenes.

1. Alkanes: Alkanes are also known as paraffins. They are saturated hydrocarbons, meaning that all carbon-carbon bonds are single bonds and each carbon atom is bonded to the maximum number of hydrogen atoms. The general formula for alkanes is CnH2n+2, where “n” represents the number of carbon atoms in the chain. Examples include methane (CH4), ethane (C2H6), propane (C3H8), and so on.
2. Alkenes: Alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond (C=C). Due to the presence of the double bond, alkenes have fewer hydrogen atoms than the corresponding alkanes with the same number of carbon atoms. The general formula for alkenes is CnH2n, where “n” again represents the number of carbon atoms. Examples include ethene (C2H4), propene (C3H6), and butene (C4H8).

Aliphatic hydrocarbons play important roles in various industries. They are commonly found in petroleum and natural gas deposits, where they serve as the main constituents of fuels. These compounds can undergo various chemical reactions, including combustion, hydrogenation, and polymerization, leading to the production of a wide range of products such as plastics, solvents, lubricants, and more.

It’s worth noting that aliphatic hydrocarbons stand in contrast to aromatic hydrocarbons, which are characterized by the presence of one or more aromatic rings (e.g., benzene) and exhibit different chemical properties and reactivity.