Question

The decomposition of $KCl{O}_3$ to $KCl$ and $O_2$ on heating is an example of:
A. Intramolecular of redox change
B. Intermolecular redox change
C. Decomposition or auto redox change
D. None

Answer 1

Hint: Redox reaction is a chemical reaction in which one of the reactants loses electrons means undergoes oxidation and another reactant accepts electrons means undergoing reduction reaction. Both oxidation and reduction reactions happen together in redox reactions.


Complete step by step answer:
- In the question it is given that potassium chlorate is undergoing decomposition on heating and forms potassium chloride and oxygen as the products.
- We can write the decomposition reaction of potassium chlorate on heating as follows.
$2KCl{O}_3\to 2KCl+3O_2$
- In the above reaction 2 moles of potassium chlorate undergoes decomposition and forms 2 moles of potassium chloride and three moles of oxygen as the product.
$$2K\stackrel{+5}{Cl}{\stackrel{-2}{O}}_3\to 2K\stackrel{-1}{Cl}+3{\stackrel{0}{O}}_2$$
- In the above chemical reaction the oxidation state of chlorine in $KCl{O}_3$ is +5 is changed to -1 in $KCl$ and the oxidation state of oxygen is changed from -2 to 0.
$\begin{array}{rl}& KCl{O}_3\\ & 1+x+3(-2)=0\\ & x=5\end{array}$
In the above calculation, x = oxidation state of chlorine.
- Means, chlorine is reduced (means accepted electrons) from +5 to -1 and oxygen is oxidized (lost electrons) from -2 to 0.
- Therefore, the gain and loss of electrons indicates that the redox reaction is intramolecular redox change.

- So, the correct option is A.


Note: If the exchange of electrons is happening in between one chemical in one reaction and another chemical in another reaction then the type of redox reaction is called intermolecular redox change. Redox reactions are also called disproportionation reactions.