Example of Homologous Series

Numerous organic molecules fall under the homologous series category; they are all distinguished by unique structural and chemical characteristics. Common homologous series types include the following:

Alkane Homologous Series

Alkane has general formula C_nH_2n+2, these saturated hydrocarbons are made up of carbon-carbon single bonds. Ethane (C₂H₆), propane (C₃H₈), and methane (CH₄) are a few examples. In this, each compound differ by -CH₂ from its preceding compound

Examples

• Methane (CH₄)
• Ethane (C₂H₆)
• Propane (C₃H₈)

Alkenes Homologous Series

Alkenes are unsaturated hydrocarbons with at least one carbon-carbon double bond. They are sometimes referred to as olefins. CnH₂n is their standard formula. The chemicals propene (propylene, C₃H₆) and ethene (ethylene, C₂H₄) are examples. In this, each compound differ by -CH₂ from its preceding compound

Examples

• Ethene (C₂H₄)
• Propene (C₃H₆)
• Butene (C₄H₈)

Alkynes Homologous Series

The unsaturated hydrocarbons known as alkynes have at least one triple bond between carbon atoms. CnH₂n-2 is their standard formula. Two such compounds are propyne (methylacetylene, C₃H₄) and ethyne (acetylene, C₂H₂). In this, each compound differ by -CH₂ from its preceding compound

Examples

• Ethyne (Acetylene) (C₂H₂)
• Propyne (C₃H₄)
• Butyne (C₄H₆)

Alcohols Homologous Series

These chemical substances have a carbon atom bound to a hydroxyl (-OH) functional group. C_nH_2n+1OH is their general formula. Methanol (CH₃OH), ethanol (C₂H₅OH), and propanol (C₃H₇OH) are a few examples.

Examples

• Methanol (CH₃OH)
• Ethanol (C₂H₅OH)
• Propanol (C₃H₇OH)

Aldehyde Homologous Series

Aldehyde have functional group -CHO attached to the parent carbon chain. The general formula for Aldehyde homologous series is C_nH_2n+1CHO where n starts with zero. The members of Aldehyde Homologous series are mentioned below:

• Methanal(HCHO)
• Ethanal(CH₃CHO)
• Propanal (CH₃CH₂O)

Ketone Homologous Series

Ketone has a general formula of -C-CO-C where, O is bonded to the middle carbon with double bond. Deviating from the other carbon compounds, ketone group starts with three carbon chain. Hence, the first member of Ketone Homologous series is Propanone. The first three members of Ketone Homologous Series are mentioned below:

• Propanone(CH₃COCH₃)
• Butanone(CH₃CH₂COCH₃)
• Pentanone(CH₃CH₂CH₂COCH₃)

Learn, Aldehyde and Ketone

Carboxylic Acids Homologous Series

Carboxylic Acids substances have a carboxyl (-COOH) functional group made composed of a hydroxyl (-OH) group on one carbon atom and a carbonyl (C=O) group on the other. They often have the formula C_nH_2n+1COOH. Acetic acid (CH₃COOH), propionic acid (C₂H₅COOH), and formic acid (HCOOH) are a few examples.

Examples

• Methanoic Acid (Formic Acid) (HCOOH)
• Ethanoic Acid (Acetic Acid) (CH₃COOH)
• Propanoic Acid (Propionic Acid) (C₂H₅COOH)

Amines Homologous Series

These are organic compounds that are created by substituting alkyl or aryl groups for one or more hydrogen atoms in ammonia (NH₃). One nitrogen atom with one lonely pair of electrons is present in them. Methylamine (C₂H₅NH₂), aniline (C₆H₅NH₂), and methylamine (CH₃NH₂) are a few examples.

Examples

• Methylamine (CH₃NH₂)
• Ethylamine (C₂H₅NH₂)
• Propylamine (C₃H₇NH₂)

Homologous Series is a family of organic compounds where two consecutive members in the family differ from each other by -CH₂ repeating unit. The mass difference between two such consecutive members is 14 units. They have same functional groups and show similar trends in physical and chemical properties.

This article deals with definitions, formulas, and examples of homologous series. A table discussing all the possible homologous series has been also added to the article. We have to study Homologous Series in Class 10 in the chapter on Carbon and its compound.