Hypoiodic acid

The possibility that a number of iodinations with iodine and iodine monochloride may involve the molecular species rather than the positive species are formerly believed has been considered under positive iodination (see pp. 92-97). Briefly, iodination rates have been found to be proportional to [I-]-2 and [I ] 1, generally with a mixed dependence, and the former term has been interpreted as involving iodination by hypoiodous acid (or more likely, positive iodine) and the latter term attributed to iodination by molecular iodine. 

D.10 The following acids are used in chemical laboratories, although they are less common than those in Exercise D.9. Write the formula of (a) perchloric acid (b) hypochlorous acid (c) hypoiodous acid (d) hydrofluoric acid (e) phosphorous acid (f) periodic acid. 

Autoprotolysis also contributes to the pH of very dilute solutions of weak acids. In fact, some acids, such as hypoiodous acid, HIO, are so weak and undergo so little deprotonation that the autoprotolysis of water almost always contributes significantly to the pH. To find the pH of these solutions, we must take into account the autoprotolysis of water. 

Identify the oxidation number of the halogen in (a) hypoiodous acid (b) CIO, (c) dichlorine heptoxide ... 

What we have is a solution of two weak acid, hypochlorous acid (HOC1) and hypoiodous acid (HOI) ... 

Kv is the self-ionization constant for water (Table 3.2) and equation (3.18) reflects the not surprising inverse relation between Ka and Kh. It is only when Ka and Kv for a compound are of different magnitudes that it may be classified as an acid or a base. An example which is difficult to classify is hypoiodous acid (HOI) where K = 2.5 x lO11 mol dm 3 andKh = 3.2 x 10 10 mol dm3. Although Kb has been widely used in the past, it is a quantity which is largely redundant, for Ka (or pKa) may be used to express the strength of bases as well as acids, see Table 3.3. 

Bichsel Y, Von Gunten U (1999) Oxidation of iodide and hypoiodous acid in the disinfection of natural waters. Environ Sci Technol 33(22) 4040 045... 

The much slower reaction of the eiramid fiber with iodine than with chlorine has been shown before (7) and most likely derives from the different dissociation constants, For hypoiodous acid at the conditions used in the RO plant = 4.5 x 10 com-... 

A relatively stable aqua complex or protonated hypoastatous acid [H20At] has been assumed similarly, a protonated hypoiodous acid has been reported to exist in aqueous solutions (15). The equilibrium constant for the deprotonation reaction [Eq. (9)] has been estimated by extrapolation of data accrued from the lighter halogens to be < 10" (80), indicating that [H20At]" is a fairly weak acid. Another structure, the symmetric diaqua cationic complex [H20-At-0H2]", has also been proposed (79, 80). 

It also may be prepared by treating hypoiodous acid with a base ... 

Hypoiodous acid may be obtained by alkabne hydrolysis of iodine at pH 12 ... 

In aqueous solutions, iodine hydrolyzes to hypoiodous acid, hydrogen ion and iodide anion ... 

All forms of iodine including the elemental iodine, hypoiodous acid (HOI), hypoiodite anion (OI ), free iodide anion (I-), and triiodide anion (I3 ) in water also may be measured by the Leuco crystal violet method. The sample is treated with potassium peroxymonosulfate to oxidize all iodide species in the sample. It then is treated with leukocrystal violet reagent for color development. Interference from free chlorine may be eliminated by addition of an ammonium salt. 

Under milder conditions and in equimolar ratio, hypoiodous acid forms ... 

Hypoiodous acid, deprotonation, 33 89-90 Hyponitrous acid, reaction mechanisms, 22 135-137... 

Similarly, the oxidation of iodocyclohexane by DMD under a nitrogen-gas atmosphere leads to the iodohydrin and diol as unexpected products (equation 24). The iodohydrin, formed as the major product, clearly reveals that hypoiodous acid (HOI) is generated in situ, which adds to the liberated cyclohexene. Indeed, when methyl iodide (Mel) is oxidized by DMD at subambient temperature in the presence of cyclohexene, the corresponding iodohydrin is obtained in very good yield The latter method may be utilized for the preparation of allylic alcohols with a vinylic iodo functional group from allenes (equation 25) . ... 

Hock-cleavage, hpid oxidation, 946 HOI see Hypoiodous acid HomoaUyhc alcohols, transition metal peroxide oxidation, 1089-94... 

Hypoiodous acid (HOI), generation in dioxirane oxidation, 1158 Hypothiocyanite, from lactoperoxidase, 612... 

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