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Combustion is described as an exothermic oxidation. Which pair of features best supports this description?
AIt releases heat while combining with oxygen
BIt absorbs heat while losing oxygen
CIt releases heat while losing oxygen
DIt absorbs heat while combining with oxygen
Answer & Solution
Correct answer: A. It releases heat while combining with oxygen
1. In combustion a reactant rapidly combines with oxygen, which makes it an oxidation.
2. Combustion gives out heat, so it is exothermic.
3. So combustion both releases heat and combines with oxygen; options describing heat absorption or oxygen loss contradict this.
4. Therefore it releases heat while combining with oxygen.
_Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 10 Types of Chemical Reactions "Combustion Reactions", p.150_
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