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I have a feeling that I have heard of an exception - either based on the material or the oxidizer.

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    $\begingroup$ I wouldn't think of combustion as necessarily a redox reaction. For instance burning methane doesn't seem like a redox reaction to me. $\endgroup$
    – MaxW
    Oct 27, 2017 at 20:43
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    $\begingroup$ @MaxW It kind of is though. You're oxidizing a methane in a relatively uncontrolled setting. You might also consider a putative methane fuel cell which certainly suggests a redox. Still, I agree that it's usually best not to think of combustion in redox terms. There's not much to be gained even if it is a redox reaction. $\endgroup$
    – Zhe
    Oct 28, 2017 at 2:12
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    $\begingroup$ @Zhe When I learnt redox reactions at school, we took the detour via combustion reactions (of magnesium, mainly) to reach the concept. $\endgroup$
    – Jan
    Oct 28, 2017 at 5:36
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    $\begingroup$ @Enthuziast That's not the way things work. Feelings are not studied in chemistry. Bring us an example, then we'll see. Short of that, it's nonsense. $\endgroup$ Oct 28, 2017 at 8:59
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    $\begingroup$ No.$\mathstrut$ $\endgroup$ Oct 29, 2017 at 5:16

2 Answers 2

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Yes, every combustion reaction is a redox reaction. Combustion is an exothermic reaction of a fuel and an oxidant (that's a big clue). Most commonly, the oxidant is oxygen, which is reduced to water in the process. The other products will depend on the fuel. Organic compounds will have carbon atoms of various oxidation states that will be oxidized to the +4 state as carbon dioxide product.

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    $\begingroup$ And there are no exceptions, for example a reaction with Sulfur as fuel (same group as Oxygen) and Oxygen as oxidant? Any idea why I have the belief that I learnt that there are exceptions? $\endgroup$
    – Enthuziast
    Oct 28, 2017 at 5:22
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    $\begingroup$ @Enthuziast burning sulfur gives sulfur oxides, where sulfur has been oxidized and oxygen reduced. $\endgroup$
    – jerepierre
    Oct 28, 2017 at 6:05
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Combustion is also called oxidation of a hydrocarbon, however, this means that a hydrocarbon become oxidized while oxygen atom will be reduced. Almost every reaction involves the transfer and gaining of electrons. So since redox is reduction and oxidation then combustion is a redox reaction.

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