Question

What is meant by an addition reaction? Give an example (with equation) of an addition reaction of an alkene.

Answer 1

When an unsaturated hydrocarbon combines with another substance to form a single product, the reaction is termed as an addition reaction. Addition reactions are undergone by all alkenes and alkynes containing either a double bond or a triple bond.

Example: When ethene (C₂H₄) reacts with hydrogen in the presence of a nickel catalyst, ethane is formed. Addition of hydrogen converts the unsaturated hydrocarbon having a double bond to a saturated hydrocarbon comprising a single bond.

Let us look at the chemical equation of the addition reaction:

`CH_2 = CH_2 + H_2 -> CH_3 - CH_3`