Question

# On heating, chloric acid decomposes to:A. $HCl{{O}_{4}},\text{ }C{{l}_{2}},\text{ }{{O}_{2}},\text{ }{{H}_{2}}O$B. $HCl{{O}_{2}},\text{ }C{{l}_{2}},\text{ }{{O}_{2}},\text{ }{{H}_{2}}O$C. $HClO,\text{ }C{{l}_{2}}O \text{ }and \text{ }{{H}_{2}}{{O}_{2}}$D. $HCl,\text{ }HClO,\text{ }C{{l}_{2}}O \text{ }and \text{ }{{H}_{2}}O$

Hint: Chloric acid has molecular formula $HCl{{O}_{3}}$. It is an oxoacid of chlorine. It is also an oxidizing agent and a strong acid. At high temperatures, it decomposes to give many products.

Complete answer: - It is found that Chloric acid is thermodynamically unstable in nature.
- It is also seen that in cold aqueous solution Chloric acid is stable, to about a concentration of 30%.
- And by evaporation under reduced pressure, a solution up to 40% can be also prepared.
- If the temperature exceeds these temperatures, then it is found that Chloric acid decompose to give many products.
- We can see that on heating beyond these temperatures, the following reaction takes place:
$3HCl{{O}_{3}}\xrightarrow{\Delta }HCl{{O}_{4}}+C{{l}_{2}}+2{{O}_{2}}+{{H}_{2}}O$
- Here, we can see the products obtained are: perchloric acid, chlorine, oxygen and water.
- Hence, we can conclude that the correct option is (A), that is on heating, chloric acid decomposes to $HCl{{O}_{4}},\text{ }C{{l}_{2}},\text{ }{{O}_{2}},\text{ }{{H}_{2}}O$.

Additional Information: - It is found that Chloric acid is generally corrosive to various metals.
- We should be careful while using it because it also accelerates the burning of various combustible materials.

Note: - One should not get confused between chloric acid and perchloric acid. Chloric acid is$HCl{{O}_{3}}$ whereas perchloric acid is $HCl{{O}_{4}}$.
- It is also found that Perchloric acid is stronger acid than Chloric acid. Perchloric acid is generally the strongest acid of all the known simple acids.