Question

The following reaction is used for the preparation of oxygen gas in the laboratory $2{\mathrm{KClO}}_3\left(\mathrm{s}\right)\stackrel{\mathrm{Heat}}{\to }2\mathrm{KCl}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)$. Which of the following statement(s) is(are) correct about the reaction?

• A. It is a decomposition reaction and endothermic in nature.
• B. It is a combination reaction.
• C. It is a decomposition reaction and accompanied by the release of heat.
• D. It is a photochemical decomposition reaction and exothermic in nature.

Answer 1

The correct option is A

It is a decomposition reaction and endothermic in nature.

Explanation for correct option:

A. It is a decomposition reaction and endothermic in nature.

Reaction for the preparation of oxygen gas:

• When Potassium chlorate$\left({\mathrm{KClO}}_3\right)$ is heated, it yields Potassium chloride$\left(\mathrm{KCl}\right)$ and oxygen$\left({\mathrm{O}}_2\right)$.
• The chemical reaction can be depicted as:

$2{\mathrm{KClO}}_3\left(\mathrm{s}\right)\stackrel{\mathrm{Heat}}{\to }2\mathrm{KCl}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)$

• It is endothermic in nature.
• This reaction is a decomposition reaction, i.e. A decomposition reaction can be defined as a chemical reaction in which one reactant breaks down into two or more products.

Explanation for incorrect options:

B. It is a combination reaction.

• The reaction for the formation of oxygen is a decomposition reaction.

C. It is a decomposition reaction accompanied by the release of heat.

• It is an endothermic reaction.

D. It is a photochemical decomposition reaction and exothermic in nature.

• This reaction does not involve sunlight and it is not exothermic in nature.

Hence, the correct option is A i.e. It is a decomposition reaction and endothermic in nature.