Chlorate ions

The standard potential for the anodic reaction is 1.19 V, close to that of 1.228 V for water oxidation. In order to minimize the oxygen production from water oxidation, the cell is operated at a high potential that requires either platinum-coated or lead dioxide anodes. Various mechanisms have been proposed for the formation of perchlorates at the anode, including the discharge of chlorate ion to chlorate radical (87—89), the formation of active oxygen and subsequent formation of perchlorate (90), and the mass-transfer-controUed reaction of chlorate with adsorbed oxygen at the anode (91—93). Sodium dichromate is added to the electrolyte ia platinum anode cells to inhibit the reduction of perchlorates at the cathode. Sodium fluoride is used in the lead dioxide anode cells to improve current efficiency. 

Caro s acid has been used ia AustraUa as an oxidant ia the acid-leaching of uranium ores. It acts by oxidising the iron present ia the solution from Fe " to Fe ". This Fe " then oxidizes the uranium. Alternative oxidants that have been used iaclude pyrolusite and chlorate ion. These are both undesirable because their effluents, containing Mn " or CF, contaminate watercourses. 

In solution, chlorine dioxide decomposes very slowly at ambient temperatures in the dark. The primary decomposition process is hydrolysis of chlorine dioxide into chlorite and chlorate ions. The hydrolysis rate is a function of the concentration of hydroxyl ions and temperature, proceeding rapidly at solution pH values above 10 ... 

Large-Scale Industrial Production. Large amounts of chlorine dioxide ate used in pulp bleaching and smaller quantities ate used for the manufacture of sodium chlorite. In these appHcations, sodium chlorate is the only commercially available taw material. Chlorine dioxide production from sodium chlorate is achieved by the reduction of the chlorate ion in the presence of strong acid. The reaction consumes acid, so that acid and reducing agents must be constantly added to maintain the reaction. 

Pulp bleaching with chlorine dioxide is most often performed at an acidic pH, so that the final pH of the bleach Hquor is in the range of 2—5. Under these conditions, the residual concentration of chlorite and chlorate ions in the bleach Hquor are minimized and chloride ion is the predominant chlorine species in the spent bleach (77). In addition to direct addition to pulp in bleaching, chlorine dioxide also finds use in wastewater treatment from pulp mill operations as a means to remove effluent color (85). 

In the presence of added chloride, chlorate ion is formed in negligible amounts. 

B. Slootmaekers, S. Tachiyashiki, D. Wood, and G. Gordon, "The Removal of Chlorite Ion and Chlorate Ion from Drinking Water," in Chlorine Dioxide Scientific, Tegulatory and Application Issues, American Water Works Association, International Sjmposium, Denver, Colo., Nov. 1—2,1989. 

Chlorate Analysis. Chlorate ion concentration is determined by reaction with a reducing agent. Ferrous sulfate is preferred for quaHty control (111), but other reagents, such as arsenious acid, stannous chloride, and potassium iodide, have also been used (112). When ferrous sulfate is used, a measured excess of the reagent is added to a strong hydrochloric acid solution of the chlorate for reduction, after which the excess ferrous sulfate is titrated with an oxidant, usually potassium permanganate or potassium dichromate. 

C—O bonding and Cl—F fission of the intermediate cw-fluoro chlorate (29a), which in turn undergoes oxidation to the fluoro ketone (25) by a concerted elimination of chlorous acid. A similar transition state (30) approximating an allylic carbonium ion could be involved in the reaction of the dienol derivatives (6) with perchloryl fluoride, which would be expected to give rise to the c/5-adduct (30a). Reaction of the latter with water leads to product and chlorate ion. 

ChloratioD, /, chlorination, — n. chlorate ion, Chloratspreng-mittel, n, -stoff, m. chlorate explosive,... 

Charles, Jacques, 57 Charles law, 58 Chemical bonding, see Bonding Chemical bonds, see Bond Chemical change, 38 Chemical energy, 119 Chemical equations, see Equations Chemical equilibrium, law of, 152 Chemical formulas, see Formula Chemical kinetics, 124 Chemical reactions, see Reactions Chemical stability, 30 Chemical symbols, 30 not from common names, 31 see inside back cover Chemotherapy, 434 Chlorate ion, 360 Chloric acid, 359 Chlorides chemistry of, 99 of alkali metals, 93,103 of third-row elements, 103 Chlorine... 

Discussion. Chlorate ion is reduced by warming with excess of iron(II) in the presence of a relatively high concentration of sulphuric acid ... 

Write the Lewis structure, including typical contributions to the resonance structure (where appropriate, allow for the possibility of octet expansion), for (a) dihydrogen phosphate ion (b) chlorite ion (c) chlorate ion (d) nitrate ion. 

Chlorate ions, CIO (oxidation state +5), form when chlorine reacts with hot concentrated aqueous alkali ... 

The kinetics of the reduction of chlorate ion by Ir(III) have been determined by controlled-potential electrolysis to be ... 

It was observed by Gleu that chlorate ions can be rapidly reduced by arsenic-(III) during the reaction between arsenic(III) and cerium(IV). Csanyi and Szabo have established that induced reduction can be carried out by other 1-equivalent reagents, e.g. cobalt(III), manganese(III), permanganate while 2-equivalent reagents, e.g. bromine, chlorine, periodate, proved to be inactive. 

When chlor-alkali electrolysis is conducted in an undivided cell with mild-steel cathode, the chlorine generated anodically will react with the alkali produced cathodically, and a solution of sodium hypochlorite NaClO is formed. Hypochlorite ions are readily oxidized at the anode to chlorate ions this is the basis for electrolytic chlorate production. Perchlorates can also be obtained electrochemically. 

The pregnant solution is then treated with sulfur dioxide gas by which the reduction of the chlorate ions contained in the solution takes place according to the reaction ... 

In 2.50mol BafCIO,),. ia) how many moles of barium ions are present (b) How many moles of oxygen atoms are present (c) How many moles of chlorate ions are present ... 

Ans. The first is a compound, chlorine trioxide the second is an ion, the chlorate ion. The chlorate ion has one extra electron, as shown by the minus sign. 

In basic solution, C102 disproportionates to produce chlorite and chlorate ions. 

All four ions have three oxygen atoms surrounding a nonmetal, but the nonmetals (B, C, S and Cl) are from different groups. The borate ion (Group 3 A) does not obey the octet rule, but the carbonate, sulfite and chlorate ions can be drawn so that the ions obey the octet rule. The carbonate ion clearly exhibits resonance. 

A nanofiltration membrane will always allow the chloride and chlorate ions to pass... 

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