Advanced Topic 664 of 1102 Inorganic Chemistry
Oxoacids of Chlorine
HClO, HClO2, HClO3 and HClO4 increase in acidity with oxidation state.
In-depth explanation of Oxoacids of Chlorine
Chlorine forms four common oxoacids: hypochlorous acid, HClO, chlorous acid, HClO2, chloric acid, HClO3, and perchloric acid, HClO4, with chlorine in oxidation states +1, +3, +5 and +7. Acid strength increases with the oxidation state of chlorine, because the conjugate base is more stable when more oxygen atoms share its negative charge. Perchloric acid is one of the strongest known acids, and dilute solutions are non-oxidizing. Hypochlorous acid is a weak acid that forms when chlorine dissolves in water. Its salts are the active ingredients of bleach.
Going deeper: Oxoacids of Chlorine
Key ideas: HOCl (+1), HClO2 (+3), HClO3 (+5), HClO4 (+7). Acid strength rises with oxidation state and number of terminal O: HClO4 is the strongest common acid, pKa about -10, HOCl is weak with pKa 7.5. Conjugate bases are ClO-, ClO2-, ClO3- and ClO4-, with stability to disproportionation increasing. Oxidizing power per mole is highest for hypochlorite and falls with kinetic stability, since perchlorate is sluggish in cold dilute solutions.
Common mistakes and connections: Students believe more oxygen means stronger oxidizer; thermodynamically yes, but perchlorate is kinetically slow to react at room temperature. Hot concentrated HClO4 is explosive with organics. The strength trend is explained by resonance stabilization of the anion and the inductive effect of terminal oxygens. Links to acid strength, Pauling rules and disproportionation.
Visualization of Oxoacids of Chlorine
Acid strength rises with the chlorine oxidation state (+1 to +7), so HClO4 is one of the strongest acids and HClO the weakest. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Sodium hypochlorite in household bleach slowly decomposes, especially in light, and loses its disinfecting strength.
Frequently asked questions about Oxoacids of Chlorine
What is Oxoacids of Chlorine?
HClO, HClO2, HClO3 and HClO4 increase in acidity with oxidation state.
Is Oxoacids of Chlorine a beginner, intermediate or advanced topic?
Oxoacids of Chlorine is a advanced topic in Inorganic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Oxoacids of Chlorine?
Study these earlier topics in Inorganic Chemistry first: Hydrogen Halides, Hydrofluoric Acid, Interhalogen Compounds.
What comes after Oxoacids of Chlorine?
The next topics in Inorganic Chemistry are Bleaching Powder and Noble Gases.
Can I practise Oxoacids of Chlorine with quizzes?
Yes. The interactive lesson includes a self-check question on Oxoacids of Chlorine, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Oxoacids of Chlorine fits in Inorganic Chemistry
Oxoacids of Chlorine is topic 49 of 113 in Inorganic Chemistry.