If I had a box that had inside it a UV light an equal quantity of ozone ($\ce{O3}$), and $\ce{H3O+}$, which would be broken down because of the UV light to $\ce{O}$, and $\ce{O2}$, as well as $\ce{H2O}$, and $\ce{H+}$ because that is what the $\ce{H3O+}$ would be broken down into. If I introduced one hypochlorite Ion ($\ce{ClO-}$) or a chloride Ion ($\ce{Cl-}$), what would the chloride Ion or hypochlorite Ion react with? Would it react with the $\ce{H+}$, or the $\ce{O}$ & $\ce{O2}$?


First of all, hydronium ion, $\ce{H3O+}$ is basically a proton in aqueous solution. A proton undergoes hydrogen bond in aqueous solution to forms various forms of hydrated proton. But for simplicity, we denote $\ce{H+}$ which is considered an acid. Now, UV light dissociates hydronium ion in ozone atmosphere into oxygen, singlet oxygen, proton and water. So, if hypochlorite salt or its corresponding acid is introduced, it might react with these. Chloride ion in form of salts is very much stable and is unlikely to react with any of the dissociated products.

So, first of all, any hypochlorite salt or hypochloric acid added will dissociate into component ion in presence of UV light. Then will react with the following dissociated products:

  1. Singlet oxygen

$$\ce{ClO- + 2O ⇄ ClO3-}$$

(Source, considered hypochloric acid)

  1. Proton

$$\ce{2HClO + 2 H+ + 2  e{−} ⇌ Cl2(g) + 2H2O}$$

Water is present as moisture so it is unable to attack hypochlorite ion readily. Also oxygen is present in minute amount(mainly singlet oxygen is present), so it cannot oxidize hypochlorite ion.

  • $\begingroup$ So would the CLO- react with the H+ or the O family (O, O2)? $\endgroup$ – Arjun Jhaveri Jun 6 '17 at 15:01
  • $\begingroup$ @ArjunJhaveri Both, but in the O family, only singlet oxygen will react. $\endgroup$ – Nilay Ghosh Jun 6 '17 at 15:45
  • $\begingroup$ What would it react with first? Also, Over time, would all of the the H+ ions precipitate back and not bond with the chlorine because they form water? $\endgroup$ – Arjun Jhaveri Jun 6 '17 at 17:12
  • $\begingroup$ @ArjunJhaveri everything is possible. The reaction proceed in such a complex way that nothing can be said clearly. Indeed, hypochlorite ion is not that kind of thing you daily work with nor they can be found in labs so working with them require higher understanding of chemistry. Indeed, it is unstable and undergo numerous acid, it may form chloric acid, it may dehydrate to chlorine dioxide. So, nothing can be said clearly. $\endgroup$ – Nilay Ghosh Jun 6 '17 at 18:23

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