Properties of Alkanes and Alkenes

May I know which of the above is....
1) More flammable?
2) Burns with a smokier flame?

Thank you :)

Its logical to expect gas with multiple bond to be more inflammable (that is the right word for combustible gas)
The gas which has greater C content per mole sholud burn with a more smoky flame . So its again alkene and not alkane.

The alkenes are highly flammable and burn readily in air, forming carbon dioxide and water,. For example, ethene burns as follows :


C2H4 + 3 O2 ==> 2 CO2 + 2 H2O

Nothing happens when alkanes are merely mixed with oxygen (O2) at room temperature, but when a flame or spark provides the activation energy, a highly exothermic combustion reaction proceeds vigorously. For methane (CH4), the reaction is as follows:

CH4 + 2O2 → CO2 + 2H2O + heat

Therefore Alkenes are more flammable than alkanes.

Low molecular weight alkanes and alkenes are gases at room temperatures and pressures; as the molecular weight increases, these hydrocarbons become liquids and then solids.
For alkenes and branched hydrocarbons, the geometry of the molecule can be more important than the number of carbons
The alkenes are highly flammable and burn readily in air, forming carbon dioxide and water
Alkenes burn with a luminous flame to give carbon dioxide and water. The flame

becomes luminous because of the higher carbon content of alkenes than alkanes

Yes, you may know ;D
1) Alkenes - because they have a double bone which is readily reactive
2) Alkanes - because it is a saturated hydrocarbon

Alkenes are more flammable because they are unsaturated and their carbon-carbon double bond can be broken easily.hence alkene will produce a smokier flame.