Hypochlorous Acid - HOCl

What is Hypochlorous Acid?

HOCl is a weak acid with chemical name Hypochlorous Acid. It is also called Hydrogen hypochlorite or Chlorine hydroxide or hypochloric acid. It was discovered by a French chemist Antoine Jerome Balard in the year 1834. It is an oxyacid of chlorine.

It contains monovalent chlorine that functions as a reducing agent or an oxidizing agent. It is an unstable acid and functions as a human metabolite. It belongs to the family of reactive oxygen species and is a conjugate acid of a hypochlorite.

Properties of Hypochlorous Acid – HOCl

HOCl Hypochlorous Acid
Molecular weight of HOCl 52.457 g/mol
No. of hydrogen bond acceptor 1
Monoisotopic mass of Hypochlorous Acid 51.972 g/mol
No. of hydrogen bond donor 1

Hypochlorous Acid structure – HOCl

Hypochlorous Acid structure

HOCl Uses (Hypochlorous Acid)

  • Hypochlorous Acid is used to convert alkenes to chlorohydrins.
  • Used in cosmetics such as baby products.
  • Used in swimming pools.
  • Used to generate sufficient quantities of safe disinfectant.
  • Used in marine sanitation devices to convert seawater into HOCl.
  • Used as a wound care agent.
  • Used to treat various infections in pets and humans.


    • Hypochlorous acid partially dissociates into the anion hypochlorite ClO in aqueous solutions. Below is the reaction:

HClO ⇌ ClO + H+

Hypochlorites are the salts of hypochlorous acid. One of the common hypochlorites is sodium hypochlorite (NaClO), which is an active ingredient in bleach.

    • At standard conditions Hypochlorous Acid is a stronger oxidant when compared to chlorine.

2 HClO(aq) + 2  H+ + 2  e ⇌ Cl2(g) + 2 H2O

Where, E = +1.63 V

    • Hypochlorous acid reacts with hydrochloric acid (HCl) to produce chlorine gas:

HClO + HCl → H2O + Cl2

    • Hypochlorous acid reacts with amines to produce chloramines along with water.

NH3 + HClO → NH2Cl + H2O

Frequently Asked Questions

What are the uses of hypochlorous acid?

Hypochlorous acid is commonly used as a disinfectant in sanitizing wash solutions and swimming pools. For such applications, chlorine is applied to water to dissolve the reactive chemicals in the solution.

What happens when acids are added to aqueous salts of hypochlorous acid?

By adding acids to the aqueous salts of hypochlorous acid (such as sodium hypochlorite in commercial bleach solutions), the resulting reaction is pushed to the left and chlorine gas is created. Thus, dissolving chlorine gas into simple water solutions, such as sodium hydroxide, promotes the creation of solid hypochlorite bleaches.

How does hypochlorous acid react with amino acids?

Hypochlorous acid reacts readily with amino acids possessing side-chains of the amino group, with HClO chlorine displacing a hydrogen resulting in organic chloramine. Chlorinated amino acids decompose quickly, but protein chloramines last longer and retain some oxidative ability.

Learn more about the Structure, physical and chemical properties of HOCl from the experts at BYJU’S.

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