Alkene
Definition and meaning of Alkene in chemistry.
An alkene is an unsaturated hydrocarbon containing at least one carbon-carbon double bond. Alkenes follow the general formula CnH2n for non-cyclic structures and are more reactive than alkanes due to this double bond.
In more detail
The carbon-carbon double bond consists of a sigma bond and a pi bond; the weaker pi bond makes alkenes susceptible to addition reactions, where atoms or groups add across the double bond to form single bonds. Alkenes are crucial in organic synthesis and industrial chemistry, serving as starting materials for polymers, alcohols, and numerous other compounds. They occur naturally in plant oils, terpenes, and as plant hormones. Common reactions include hydrogenation (addition of hydrogen), halogenation (addition of halogens), and hydration (addition of water).
Key facts
| Chemical Formula (Ethene) | C2H4 |
|---|---|
| General Formula (Acyclic) | CnH2n |
| Functional Group | Carbon-carbon double bond (C=C) |
| Field | Organic Chemistry |
Ethene (C2H4), also called ethylene, is the simplest alkene and is industrially important for producing polyethylene plastic and as a naturally occurring plant hormone that regulates ripening in fruit.
Frequently asked questions
Why are alkenes more reactive than alkanes?
The pi bond in the carbon-carbon double bond is weaker and more exposed than single bonds in alkanes, making alkenes readily undergo addition reactions.
What is an addition reaction?
An addition reaction occurs when atoms or groups add directly across the double bond, converting C=C to C-C with new substituents, such as when hydrogen adds to form an alkane.