Answer:
The compounds are arranged from the least heat of combustion to the highest (in order of increasing heat of combustion).
Propane--> butane --> pentane.
Step-by-step explanation:
Hydrocarbons are compounds which contains carbon and hydrogen only. Alkane is called a saturated hydrocarbon because all four bonds of carbon are single bonds. Examples of alkanes include: pentane, propane and butane. One of the chemical properties of alkanes includes combustion reaction.
In COMBUSTION REACTION, alkanes burns in air (oxygen) to produce carbon dioxide and water.The heat released on complete combustion of one mole of a substance is called HEAT OF COMBUSTION.
The heat of combustion of saturated hydrocarbon ( alkanes) increases with increase in number of carbon atoms in a molecule. This is due to more carbon available for burning and more number of bonds undergoing changes. Therefore in the arrangement of the given compounds, PENTANE has the highest heat of combustion while PROPANE is the least.