A concept problem on organic chemistry

[jeremy22511]

Alkanes are saturated hydrocarbons which are very unreactive.
However, they undergo combustion, i.e. they react with oxygen. Why?

(Even compounds as unreactive as polythene with over thousands of carbon atoms per molecule undergoes combustion...)

 

[sjb-2812]

Perhaps look into activation energy or similar?

 

[alxm]

Why says alkanes aren't reactive? Alkanes are fairly reactive, or we'd use PE instead of glassware in the lab.

Noble gases are unreactive. Nitrogen is fairly unreactive. PTFE is fairly unreactive. But alkanes? No. They react with all sorts of things.

 

[jeremy22511]

But my textbook says they don't react with acids, alkalis, dehydrating agents, O.A., R.A. etc. It was this that gave me the idea that alkanes are chemically stable...
Can anyone help me? Thanks.

J

 

[chemisttree]

Fire is a free radical process and alkanes DO undergo free radical reactions.