Similarities and differences between alkanes and alkenes

SIMILARITIES:

• Both are insoluble in water
• Both are neutral
• Both burn in excess air to produce carbon dioxide and water.

DIFFERENCES:

Alkanes:

• General formula: C_nH_2n+2
• Saturated hydrocarbon
• Do not decolourise the purple acidified potassium manganate (VII) solution.
• Do not decolourise the reddish-brown bromine solution.
• Burn with a less sooty flame because the percentage by mass of carbon is lower than that of the corresponding alkenes. 

Alkenes

• General formula: C_nH_2n
• Unsaturated hydrocarbon
• Decolourise the purple acidified potassium manganite (VII) solution.
• Decolourise the reddish-brown bromine solution.
• Burn with a more sooty flame because the percentage by mass of carbon is higher than that of the corresponding alkanes.