Hypochlorous Acid Formula

Hypochlorous Acid

Hypochlorous acid is a weak unstable acid that naturally forms when chlorine dissolves in water. Most noteworthy, we know it by many names such as chloric acid, hydrogen hypochlorite, chlorine hydroxide, and chloranol. Furthermore, it cannot be isolated from these solutions due to the rapid equilibrium with its precursor. Also, it is a participant of reactive oxygen species and a chlorine oxoacid and a conjugate acid of hypochlorite. Learn Hypochlorous Acid Formula here.

Hypochlorous Acid Formula and Structure

Its chemical formula is HOCl and on a molecular level, we can write it as HClO. Its molar mass is 52.46 g.mol. In addition, it is a simple molecule with oxygen in the center which connects with the chlorine and hydrogen atoms through a single bond. Besides, in the common representation we can write its chemical structure as shown in the image below:

The Occurrence of Hypochlorous Acid

It commonly occurs in the human body. The immune system of the human body produces them to fight infections. Also, it acts against a wide range of microorganisms.

Preparation of Hypochlorous Acid

If we add chlorine in water then it gives hypochlorous acid together with hydrochloric acid (HCl):

\( Cl_{2} + H_{2}O \rightarrow HOCl + HCl\)

This reaction is in equilibrium, and it is not easy to isolate HOCl from this mixture. But, we can obtain stable hypochlorous salt by dissolving chlorine gas into the sodium hydroxide solution, or other aqueous basic solutions.

Another method by which we can prepare it is by dissolving dichlorine monoxide in water.

\( Cl_{2}O + H_{2}O \rightarrow 2HOCl \)

Physical Properties of Hypochlorous Acid

It only exists as an aqueous solution. In addition, it is a colorless solution, and telling its precise physical properties is difficult, as they depend on how to concentrate the solution is. Dry or anhydrous hypochlorous acid is impossible to prepare since the molecule exists in equilibrium with its anhydride.

Chemical Properties of Hypochlorous Acid

It is a strong oxidizer that can form explosive mixtures. Being a weak acid, in aqueous solutions, it partially dissociates into the hypochlorite ion (\( OCl^{-}\)) and \( H^{+}\).

In addition, it reacts with bases to form hypochlorite salts. For example, When sodium hypochlorite (NaOCl), the active ingredient in bleach, is formed by reacting hypochlorous acid with sodium hydroxide.

\( HOCl + NaOH \rightarrow NaOCl + H_{2}O

Other Chemical Reaction

Hypochlorous acid partially dissociates in aqueous solution into the anion hypochlorite \( Cl^{-} \):

\( HOCl \rightleftharpoons ClO^{-} + H^{+} \)

We refer to hypochlorous acid salts as hypochlorites and one of the best-known hypochlorites is NaClO, the active ingredients in bleach.

Under standard conditions HOCl (hypochlorous acid) is a stronger oxidant than chlorine.

\( 2HOCl_{(aq)} + 2H^{+} + 2e^{-} \rightleftharpoons Cl_{2(g)} + 2H_{2} O \)

Hypochlorous acid reacts with HCl to form chlorine gas:

\( HOCl + HCl \rightarrow H_{2}O + Cl_{2}\)

It also reacts with organic amines, forming n-chloroamines.

Uses of Hypochlorous Acid

It is a more powerful oxidizer than chlorine and a very effective sanitizing agent. We use it to make sodium hypochlorite (NaOCl) and calcium hypochlorite (\( Ca (OCl)_{2} \)) that we use in the making of bleaches, disinfectants, and deodorants.

In addition, it is an active sanitizer that we use in swimming pools. We also use it as a wound disinfecting agent and a skin cleansing agent in cosmetics.

Hypochlorous Acid Health and Safety Hazard

It is not harmful at all, as the human body produces it in low concentration. Furthermore, it has an anti-microbial action.

Solved Example for You

Question: Mention a method to prepare monochloramine from hypochlorous acid?

Solution: We can prepare monochloramine by reacting ammonia with hypochlorous acid:

\( NH_{3} + HOCl \rightarrow NH_{2} Cl + H_{2} O\)