Provide an example of an addition reaction with alkenes.

An example of an addition reaction with alkenes is the reaction between ethene and hydrogen to form ethane.

Alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond. Addition reactions are reactions in which two or more reactants combine to form a single product. In the case of alkenes, addition reactions occur when the double bond is broken and new atoms or groups of atoms are added to the molecule.

One example of an addition reaction with alkenes is the reaction between ethene (C2H4) and hydrogen (H2) to form ethane (C2H6). This reaction is catalysed by a metal catalyst such as nickel or platinum, and is known as hydrogenation.

During the reaction, the double bond in ethene is broken and the two carbon atoms are each bonded to a hydrogen atom. This results in the formation of a single bond between the two carbon atoms, and the molecule becomes saturated with hydrogen atoms.

Addition reactions with alkenes are important in the production of a wide range of products, including plastics, fuels, and pharmaceuticals. Understanding the mechanisms of these reactions is therefore essential for chemists and chemical engineers working in these industries.