Alkenes and AlkynesDavid Wu

Physical Propertiesof Alkenes

Colorless & odorless (no color, no smell)

Physical State depends on molecular mass.

Physical Properties of Alkenes

The simplest alkenes, ethene, propene and butene are gases.

Linear alkenes of approximately 5 to 16 carbons are liquids, and higher

alkenes are waxy solids.

Physical State

Alkenes has a smaller density than water.

So they are insoluble in water.

Physical Properties of Alkenes

The more intermolecular mass is added, the higher the boiling point.

Intermolecular forces of alkenes gets stronger with increase in the size of the molecules.

Boiling point

Chemical propertiesof Alkenes

Relatively stable compounds

But are more reactive than alkanes due to the presence of a carbon–carbon pi-bond.

Chemical properties of Alkenes

Forming products such as halogenoalkanes, alcohols or amines.

Alkenes are raw materials for plastics such as polythene, PVC and polystyrene.

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Use of Alkenes

Physical Propertiesof Alkynes

Insoluble in water

But are fairly soluble in organic solvents (such as, alcohol, ether, acetone etc)

Physical Properties of Alkynes

Chemical Propertiesof Alkynes

The melting and boiling points of alkynes increase with molecular mass

Characteristically more unsaturated than alkenes

Usually more reactive than alkenes.

Chemical Properties of Alkynes

A carbon–carbon triple bond is also present in marketed drugs (such as the antiretroviral Efavirenz and the antifungal Terbinafine)

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Use of Alkynes