Question

All combustion reactions are redox reactions. True or false

Answer 1

Answer:

false

Explanation:

A combustion reaction is a burning process that occurs in the presence of an oxidant and a fuel. It is usually an energy releasing procedure in which the temperature of the environment is greater than that of the reactants.

Not all combustion reactions are redox reactions

In a redox reaction, one specie is oxidized and the other becomes reduced simultaneously.

Redox reactions are usually facilitated by the transfer of electron. One specie loses electrons to be gained by another specie.

Certain atoms in a combustion reaction will have to change their oxidation state.

During combustion, during combustion reaction, there is no transfer of electrons between reactants . None of the molecules changes oxidation state. For example;

   CH₄   +   2O₂       →    CO₂  +    2H₂O

The algebraic sum of all oxidation number of all atoms in a neutral compound is zero.

In the reaction above, all the atoms in going from reactants to products have a net oxidation number of zero.

carbon on both sides is 0

oxygen is 0

Hydrogen is 0

So there is no transfer electrons

Answer 2

Answer : The given statement is false.

Explanation :

Combustion reaction : It is defined as a chemical reaction in which a hydrocarbon react with oxygen to give product as carbon dioxide and water.

It is represented as,

$CH_4+2O_2\rightarrow CO_2+2H_2O$

Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases.

In redox reaction, transfer of electrons takes place.

As per question, all combustion reactions are not redox reactions because in combustion reaction,  oxidation and reduction reaction does not takes place. That means, the oxidation state of individual elements present on reactant side are same as the elements present on product side.

Hence, the given statement is false.