Iodine oxyacids

Prepare a solution of iodic acid (see p. 109) and pour it into two test tubes. Pour a potassium iodide solution into one tube. What substance evolves Pour an iron(II) sulphate solution into the other tube. What do you observe Write the equations of the reactions. What properties of iodic acid do the above experiments indicate Write the formulas of the iodine oxyacids. What oxygen compounds of iodine are known How are they prepared ... 

An acid is a distinct type of molecular compound. Most acids used in the laboratory can be classified as either binary acids or oxyacids. Binary acids are acids that consist of two elements, usually hydrogen and one of the halogens— fluorine, chlorine, bromine, iodine. Oxyacids are acids that contain hydrogen, oxygen, and a third element (usually a nonmetal). 

Upon storage, the amount of ted phosphoms in soHd white or Hquid phosphoms may increase if the material is exposed to light or contains contaminants such as iodine, sulfur, selenium, or sodium that catalyze the conversion from white to ted. Also, because white phosphoms is generally stored under water, some surface oxidation to form viscous white or colored polymeric oxyacids also occurs, especially if the oxygen content of the water can be replenished by exposure to air. 

The oxyacids of iodine are solids and will not be discussed here. Perchloric acid is the only oxyacid of bromine or chlorine which is stable in the pure state. There have been a few studies of its pyrolysis in the vapour phase. 

Concentrated nitric acid oxidizes nonmetals, such as sulfur, phosphorus, and iodine forming their oxyacids with liberation of nitric oxide. For example, cold concentrated nitric acid reacts with sulfur to form sulfuric acid ... 

With the exception of perchloric acid, the halogen oxyacids are reduced through the corresponding halogen elements to the hydracids in the case of iodic acid3 the formation of free iodine after a definite interval forms a striking example of a time reaction. 4 The formation of the element is not observed until after the disappearance of the whole of the sulphite. The mechanism of the reaction is probably as follows ... 

The largest nonmetals show coordination numbers as high as eight in the oc-tafiuoroanions, ]Fjj" and XeFg- (see Chapter 17). The corresponding oxyacids and oxyanions show a maximum coordination number of six [Sb(OH)fi]-, Te(OH)6, OI(OH)s, and [XeO, ]4- Of these, apparently only iodine shows a maximum oxidation state with a coordination number as low as four Periodic acid can exist as either 01(0H)S or HI04. 

In addition to the methods of preparation given in connection with the procedure for the acetylation of thiophene with acetyl chloride in the presence of stannic chloride, 2-acetothienone has been prepared from thiophene and either acetyl chloride or acetic anhydride in the presence of iodine, hydriodic acid, silica-metal oxides, zinc chloride, or inorganic oxyacids. It has also been prepared from thiophene and acetic acid in the presence of hydrogen fluoride or phosphorus pentoxide. The acylation in the presence of phosphorus pentoxide is particularly useful with higher aliphatic acids. ... 

There are two oxyacids lhat have iodine in Ihe +7 oxidation state. These periodic acids are HIO4 (called metaperiodic add) and HsIO (called paraperi-odic acid). The two forms exist in equilibrium in aqueous solution. 

What are the names, formulas, and electronic structures of the stable oxyacids of iodine and their anions ... 

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