What is the structure of alkynes and how do they differ from alkenes?

Alkynes have a triple bond between two carbon atoms, while alkenes have a double bond.

Alkynes are hydrocarbons that contain at least one triple bond between two carbon atoms. This triple bond consists of one sigma bond and two pi bonds. The triple bond is shorter and stronger than the double bond found in alkenes, making alkynes more reactive. The general formula for alkynes is CnH2n-2.

The triple bond in alkynes allows for the addition of two atoms or groups to each carbon atom in the triple bond. This means that alkynes can undergo addition reactions with hydrogen, halogens, and other molecules. Alkynes can also undergo substitution reactions, where one atom or group is replaced by another.

Alkynes have higher boiling points and melting points than alkanes and alkenes due to the strength of the triple bond. However, they have lower boiling points and melting points than comparable alkanes and alkenes due to their lower molecular weight.

In summary, alkynes have a triple bond between two carbon atoms, making them more reactive than alkenes. They have a higher boiling point and melting point than alkenes, but lower than comparable alkanes and alkenes. Alkynes can undergo addition and substitution reactions, making them useful in organic synthesis.