Question

: On heating $KCl{O}_3$ we get,
[A]$KCl{O}_2+O_2$
[B]$KCl+O_2$
[C]$KCl+O_3$
[D]$KCl+O_2+O_3$

Answer 1

Hint: $KCl{O}_3$ is an oxidant and may explode on prolonged exposure to heat. Potassium chlorate undergoes a decomposition reaction on heating which gives an inorganic residue. The residue thus obtained is heat resistant and is a common inorganic salt.

Complete step by step answer:
$KCl{O}_3$ or potassium chlorate is a white crystalline compound which produces oxygen when heated in presence of a catalyst.
When heated in presence of a catalyst, like manganese dioxide it gives oxygen and an ionic inorganic salt, potassium chloride. The reaction is-
$$2KCl{O}_3(s)\to 2KCl(s)+3O_2(g)$$
As we can see from the above reaction, 2 moles of potassium chlorate gives 3 moles of oxygen gas and 2 moles of potassium chloride.
However, in absence of a catalyst, the reaction moves forward differently.
 On heating without a catalyst, potassium chlorate turns into potassium perchlorate which on further heating decomposes into oxygen and potassium chloride. The reaction is-
$$\begin{array}{rl}& 4KCl{O}_3\to 3KCl{O}_4+KCl\\ & KCl{O}_4\to KCl+2O_2\end{array}$$
From the above reactions, we can say that 4 moles of potassium chlorate forms 3 moles of potassium perchlorate when heated. Each mole of potassium perchlorate gives 2 moles of oxygen and 1 mole of potassium chloride on further heating.
The final product obtained is the same in both the cases but the later reaction is more time consuming. Presence of a catalyst gives the product directly.
Therefore, it is clear from the above reactions that the correct answer is [B] $KCl+O_2$.

Additional information:
Potassium chlorate forms an extremely flammable mixture with combustible materials which may also be used in explosives. The mixture may ignite just by friction.

Note:
It is important to remember here that Potassium chlorate undergoes an oxidation-reduction reaction also known as red-ox reaction. Here, chlorine gets reduced and oxygen gets oxidised. Also , oxygen gas is evolved during the reaction. It is also important to remember that it does not form $KCl{O}_2$ on heating.