Hypohalous acid

Source: Wikipedia, the free encyclopedia.

A hypohalous acid is an

hydroxyl group single-bonded to any halogen. Examples include hypofluorous acid, hypochlorous acid, hypobromous acid, and hypoiodous acid. The conjugate base is a hypohalite. They can be formed by reacting the corresponding diatomic halogen molecule (F2, Cl2, Br2, I
2) with water in the reaction:

X2 + H2O ⇌ HXO + HX

This also results in the corresponding hydrogen halide, which is also acidic.

Stability

Hypohalous acids tend to be unstable. Only

hypoiodite) are also unstable, undergoing disproportionation reactions
like

3 BrO−(aq) → 2 Br−(aq) + BrO−3(aq)

and

3 HIO → 2 HI + HIO3

that result in the corresponding

halide ions and halic acids/halates.[3]

Uses

Hypochlorous acid and hypobromous acid are each dissolved in water in order to sanitize it, hypochlorous acid in swimming pools and hypobromous acid in hot tubs and spas.[4]

Acidity

Hypohalous acids tend to be

weak acids, and they tend to get weaker as the halogen progresses farther down the periodic table. Hypochlorous acid has a pKa of 7.53.[5] The pKa values of hypobromous acid is higher (meaning that it is an even weaker acid),[6] at 8.65. The pKa of hypoiodous acid is even higher, at 10.6.[7]

References

  1. doi:10.1002/anie.198803921
    .
  2. ^ Inorganic chemistry, Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, "Hypochlorous acid" p.442, section 4.3.1
  3. ISBN 9780123526519
    . Retrieved 24 September 2018.
  4. ISBN 9780060936778
    . Similarly, we add HOCl to swimming pools to kill bacteria.
  5. ^ Harris, Daniel C. (2009). Exploring Chemical Analysis (Fourth ed.). p. 538.
  6. ISBN 9780123526519
    . Retrieved 7 October 2018.
  7. ^ "Oxoacids | Introduction to Chemistry". courses.lumenlearning.com. Retrieved 26 February 2019. HOCl pKa = 7.5 < HOBr pKa = 8.6 < HOI pKa = 10.6
Retrieved from "https://en.wikipedia.org/w/index.php?title=Hypohalous_acid&oldid=1087173207"