What is a homologous series of organic compounds? - Leaving Cert Chemistry - Question 1 - 2011

A homologous series of organic compounds is a group of compounds that share the same general formula and differ only by a constant unit, typically a -CH₂- group.

1. General Formula: All the members of the series can be described by a general formula, such as CₙH₂ₙ₊₂ for alkanes.
2. Similar Functional Group: They possess the same functional group, which is responsible for their chemical reactivity and properties.
3. Gradation in Properties: Members of a homologous series exhibit a gradual change in physical properties (like boiling points and solubility) as the molecular weight increases.
4. Similar Chemical Properties: They demonstrate similar chemical properties due to the presence of the same functional group.
5. Method of Preparation: Members can typically be synthesized using a similar method of preparation.