Question

All combustion reactions are oxidation-reduction reactions. If true enter $1$, else enter $0.$

Answer 1

Hint:We know that combustion is an exothermic redox chemical reaction which occurs at high temperature and in presence of an oxidant.

Complete step by step answer:

All combustion reactions are oxidation-reduction reactions.
For example, consider the combustion reaction of carbon.
\[C + {O_2} \to C{O_2}\]

We know that if the oxidation state of the species decreases then it is getting reduced and it is called oxidizing agent. If the oxidation state of the species is increasing then the species is getting oxidized and it is called a reducing agent.

Calculate the oxidation number of carbon and oxygen in the given reaction.
The oxidation number of \[C\] in Carbon dioxide is \[ + 4\] and the oxidation number of Oxygen in carbon dioxide is \[ - 2\]. Thus, Carbon is oxidized and Oxygen is reduced. Hence, the combustion reaction is an oxidation-reduction reaction.

Hence the given statement is true.


Note:
-We know that oxidation state is the loss of an electron in a chemical compound. We can now see few rules of oxidation numbers.
-A free element will be zero as its oxidation number.
-Monatomic ions will have an oxidation number equal to charge of the ion.
-In hydrogen, the oxidation number is ${\text{ + 1,}}$ when combined with elements having less electronegativity; the oxidation number of hydrogen is -1.
-In compounds of oxygen, the oxidation number of oxygen will be -2 and in peroxides it will be -1.
-Group 1 elements will have +1 oxidation number.
-Group 2 elements will have +2 oxidation numbers.
-Group 17 elements will have -1 oxidation number.
-Sum of oxidation numbers of all atoms in neutral compounds is zero.
-In a polyatomic ion, the sum of the oxidation number is equal to the charge of the ion.