Alkanes and Alkenes

Both have low melting and boiling points. Their melting and boiling points increase gradually with increasing number of carbon atoms per molecule.

Changes from gas to liquid to solid as the number of carbon atoms per molecule increase.

Both have low densities. The gases and liquids are less dense than water. Density increase gradually with increasing number of carbon atoms per molecule.

Both are insoluble in water but soluble in organic solvents.

Both do not conduct electricity in any state.

Alkanes are saturated hydrocarbons, unreactive and undergo substitution reaction.

Alkenes are unsaturated hydrocarbons, reactive and undergo addition reaction.

Alkanes burn in air, producing yellow sooty flame.

Alkenes burn in air, producing yellow and very sooty flame.

Alkanes has no reaction with bromine in the dark.

Alkenes react with bromine in the dark and decolourises reddish-brown bromine.