Chemical Knowledge Share – Halic Acids

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The general chemical formula is HXO3. Haloacids are all strong acids, with their acidity decreasing in the order of chloric acid, bromic acid, and iodic acid. Halogen acids are all strong oxidizing agents. Chloric acid and bromic acid exist only in aqueous solution, while iodic acid is a colorless orthorhombic crystal. When the concentration of chloric acid exceeds 40%, it decomposes rapidly and explodes: 26HClO3＝15O2+8Cl+10HClO4+8H2O. Perbromic acid also decomposes when its concentration is greater than 50.6%. Iodic acid is relatively stable; it loses water when heated to 200°C, melts at 310°C, and decomposes into its elemental forms. A halic acid solution can be obtained by reacting dilute sulfuric acid with barium halide, followed by the removal of the precipitate. For example, Ba(BrO3)2 + H2SO4 → BaSO4↓ + 2HBrO3; iodic acid can be obtained by oxidizing iodine with strong oxidizing agents such as chlorine, nitric acid, and hydrogen peroxide. For example, 5Cl + I2 + 6H2O → HIO3 + 10HCl; 10HNO3 + I2 → 2HIO3 + 10NO2↑ + 4H2O