Organic Chemistry-Hydrocarbons – Class X & XII

Summary:

Hydrocarbons, the fundamental compounds of organic chemistry, consist solely of carbon and hydrogen atoms. They are broadly categorized into two groups: aliphatic and aromatic hydrocarbons. Aliphatic hydrocarbons can be further divided based on their structure, leading to various subtypes.

Open-chain hydrocarbons, also known as acyclic hydrocarbons, form the primary category of aliphatic hydrocarbons. Within this group are straight-chain hydrocarbons, where carbon atoms are arranged linearly, and branched chain hydrocarbons, where carbon atoms form branches in the chain.

Saturated hydrocarbons belong to the aliphatic category and have single covalent bonds between carbon atoms, resulting in each carbon atom being fully saturated with hydrogen atoms. Examples of saturated hydrocarbons include methane, ethane, propane, and butane.

Unsaturated hydrocarbons, on the other hand, contain double or triple covalent bonds between carbon atoms. They can be further divided into alkenes, containing double bonds, and alkynes, containing triple bonds. Ethene and acetylene are examples of unsaturated hydrocarbons.

Closed chain hydrocarbons, cyclic hydrocarbons or cycloalkanes, form closed or ring structures. They can be saturated or unsaturated. Examples of cyclic hydrocarbons include cyclopropane, cyclobutane, and cyclopentane.

The International Union of Pure and Applied Chemistry (IUPAC) introduced a nomenclature system to systematically name hydrocarbons.

Excerpt:

Organic Chemistry-Hydrocarbons

CHAPTER – HYDROCARBONS

Definition: Those organic compounds which contain carbon (C) and hydrogen (H) only are called “Hydrocarbons”. For example, methane (CH4), ethane (CH3CH3), propane (CH3CH2CH3) and butane (CH3CH2CH2CH3) etc.

Types of Hydrocarbons

Hydrocarbons can be classified into the following categories.
A. Aliphatic hydrocarbons B. Aromatic hydrocarbons
Definition: Those hydrocarbons (HC) which contain open chains are called “aliphatic hydrocarbons”. Aliphatic hydrocarbons can be further classified into the following categories.

i. Open chain/acyclic hydrocarbons

ii. Straight chain hydrocarbons

iii. branched chain hydrocarbons

iv. Saturated hydrocarbons

v. unsaturated hydrocarbons

vi. Closed chain/cyclic hydrocarbons

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i. Open chain/acyclic hydrocarbons
Definition: Those hydrocarbons containing an aliphatic or open chain are called “open chain/acyclic hydrocarbons”. These may be straight-chain or branched-chain hydrocarbons.

ii. Straight chain hydrocarbons
Definition: Those hydrocarbons in which carbon atoms form only linear or straight chains are called “straight chain hydrocarbons”.