The key difference between perchloric acid and hydrochloric acid is that perchloric acid has hydrogen, chlorine and oxygen atoms whereas hydrochloric acid has hydrogen and chlorine atoms only.
Both perchloric acid and hydrochloric acid are important in chemical synthesis reactions due to their strongly acidic nature. Both these are inorganic acid substances.
What is Perchloric Acid?
Perchloric acid is a mineral acid having the chemical formula HClO4. It is a stronger acid than sulfuric and nitric acids. It occurs as a colourless liquid which is odourless as well. Hot perchloric acid is a powerful oxidizer. But aqueous solutions are generally safe. Often, perchloric acid is used for the preparation of perchlorate salts, such as ammonium perchlorate, and explosive mixtures.
Perchlorate is the anion of perchloric acid, having the chemical formula ClO4–. It is an important derivative of perchloric acid which has various applications. In general, this term may refer to any compound containing perchlorate anion. The oxidation state of the chlorine atom in this compound is +7. It is the least reactive form among other chlorates. The geometry of this ion is tetrahedral.
Mostly, compounds containing this anion exists as colourless solids that are soluble in water. This anion forms when perchlorate compounds dissociate in water. In the industrial scale, we can produce this ion via electrolysis method; this involves the oxidation of aqueous sodium chlorate.
What is Hydrochloric Acid?
Hydrochloric acid is aqueous hydrogen chloride, which is a strong acid. Hydrogen chloride has the chemical formula HCl. The molar mass of this compound is 36.5 g/mol. Hydrochloric acid has a pungent odour. Moreover, it is important as a starting compound for many inorganic chemicals such as vinyl chloride.
Hydrochloric acid is considered as a strongly acidic substance because it can completely dissociate into its ions (hydrogen ion and chloride ion) and it occurs as a simple chlorine-containing acid system in an aqueous solution. This strong acid can attack our skin over a wide composition range and can cause skin burns.
Naturally, hydrochloric acid is present in the gastric acid in the digestive system of most animals, including humans. It is commercially available as an industrial chemical for the production of polyvinyl chloride for plastic. Moreover, it is used as a descaling agent in household needs, as a food additive in the food industry, in leather processing, etc.
Hydrochloric acid occurs as the salt of the hydronium ion and chloride ion. We can prepare it by treating HCl with water. HCl acid is commonly used in chemical analysis for preparation or digestion of samples for analysis. This is because concentrated HCl acid can dissolve many metals, and it can form oxidized metal chlorides with hydrogen gas.
What is the Difference Between Perchloric Acid and Hydrochloric Acid?
Perchloric acid is a mineral acid having the chemical formula HClO4 while hydrochloric acid is aqueous hydrogen chloride with the chemical formula HCl. The key difference between perchloric acid and hydrochloric acid is that perchloric acid has hydrogen, chlorine and oxygen atoms whereas hydrochloric acid has hydrogen and chlorine atoms only.
Moreover, another difference between perchloric acid and hydrochloric acid is their acidity. perchloric acid is extremely acidic while hydrochloric acid is less acidic compared to perchloric acid.
Below infographic shows more details of the difference between perchloric acid and hydrochloric acid.
Summary – Perchloric Acid vs Hydrochloric Acid
Perchloric acid and hydrogen chloride are strong inorganic acids. The key difference between perchloric acid and hydrochloric acid is that perchloric acid has hydrogen, chlorine and oxygen atoms whereas hydrochloric acid has hydrogen and chlorine atoms only.
1. “Perchloric Acid.” Wikipedia, Wikimedia Foundation, 24 June 2020, Available here.