Sulphite ions sulphate

The dichromate ion oxidises iron(II) to iron(III), sulphite to sulphate ion, iodide ion to iodine and arsenic(III) to arsenic(V) (arsenate). Reduction of dichromate by sulphite can be used to prepare chrome alum, since, if sulphur dioxide is passed into potassium dichromate acidified with sulphuric acid, potassium and chromium(III) ions formed are in the correct ratio to form the alum, which appears on crystallisation ... 

Thiosulphate and sulphite are sufficiently reducing to reduce Cu to Cu. Therefore the Cu in solutions of Cu containing sufficient thiosulphate, seleno-sulphate, or sulphite should be predominantly in the monovalent form. This would lead to the expectation that the main product will be something close to Cu2S(e). While this is often the case, CuS(e) is deposited in some cases. However, it is arguable whether this reduction of Cu is, in fact, important in practice. The reason is based on an XPS study that showed that Cu in its compounds with S, Se, and Te is normally in the monovalent state it is the chalcogenide ion (or polyion) that is believed to change oxidation states in these compounds [41]. 

Figure 2c ilustrates the influence of the sulphation on the activity of NaX zeolite in the Claus reaction.The sulphation by method A results in a very high increase in the zeolite activity. NaX sulphated by method B is also more active than pure zeolite but the growth of the activity is lower than after sulphation by method A. Such a high increase of the activity is not observed for NaY sulphated samples- According to the above discussed IR and X-ray results, one can state that hydrogen sulphite and sodium sulphate species, easily formed during NaX sulphation, cause the rise in the Claus activity. Both species react with H25 (refs.2,5,6 10). The third species i.e. aluminium sulphate seems to deactivate the catalyst- This species was observed not only after sulphation process but also after the Claus reaction on pure NaX and NaY. Sulphate ions adsorb on aluminium poison the basic sites in zeolites required in the Claus reaction. 

A kinetic study of the oxidation of sulphite ions to sulphate ions by gaseous oxygen in melts of lithium and potassium chlorides at temperatures between 414 and 504 °C has been carried out, and a possible reaction mechanism proposed.14 The interaction of oxygen at 20 °C with hydrogen sulphide presorbed at 55 °C and vice versa has been investigated.15... 

Diamines. Chromatography has been used to isolate three isomers of trans- and cis-[Co(CN)2 (RR)-cyclohexane-l,2-diamine 2] and five isomers of the corresponding propylenediamine complexes. Mer- and /ac-isomers of tris(meso-pentane-3,4-diamine)cobalt(iii) have been prepared and separated using column chromatography. The rates of aquation of three isomers of [CoCl(tmd)(dien)] and one isomer of [CoCl(tmdXdpt)] have been measured and the kinetic parameters calculated [dpt = NH2(CH2)3NH(CH2)3NH2, tmd = NH2(CH2)3NH2]. The interaction of [Co(dien)2] with sulphate, thiosulphate, sulphite, selenite, tellurite, and carbonate ions has been studied potentiometrically and stability constants determined for the outer-sphere complexes. The i.r. spectrum of octahedral... 

Tarlov and coworkers studied the mechanism of photo-oxidation of the alkanethiol monolayers on the silver surface and found that UV irradiation leads first to the scission of the C—S bond and removal of the alkane portion of the monolayer. Remaining sulphur species are then oxidized to produce sulphite and sulphate ions . As alkanesulphonate peaks were, however, observed in the aged alkanethiol monolayers on the Au(lll) surface (vide supra), the generality of this mechanism is unclear. 

In the iodometric determination method, iodine is used to oxidize the sulphite ions to sulphate ions ... 

The reaction of chlorine dioxide and sulphur(iv) has been investigated in the pH range 8—13 (phosphate and borate buffers), where in the presence of a slight excess of (sulphite) the major products are chlorite and sulphate ions with only miorr amounts of chloride and chlorate formed. In the overall reaction,... 

Sulphites react with molecular oxygen (or air) to give sulphates, a reaction catalysed by certain ions (for example Fe, Cu, arsenate(III) ion, AsO ) and inhibited by, for example, phenol, glycerol and tin(II) ions, Sn ... 

General corrosion damage was the cause of failure of an A1 alloy welded pipe assembly in an aircraft bowser which was attacked by a deicing-fluid — water mixture at small weld defects . Selective attack has been reported in welded cupro-nickel subjected to estuarine and seawater environments . It was the consequence of the combination of alloy element segregation in the weld metal and the action of sulphate reducing bacteria (SRB). Sulphide-coated Cu-enriched areas were cathodic relative to the adjacent Ni-rich areas where, in the latter, the sulphides were being continuously removed by the turbulence. Sulphite ions seemed to act as a mild inhibitor. 

Another terminal bidentate ligand that has been exploited occasionally in bright disazo direct dyes is the sulphated 8-hydroxyquinoline residue (5.15). On aftercoppering, fastness to light and wet tests is enhanced by hydrolysis catalysed by the copper(II) ion and formation of a bidentate 1 2 complex (Scheme 5.3). Apparently, electron withdrawal by sulphur facilitates removal of the sulphite grouping and approach of the copper(II) cation [10]. 

Oikawa and Saitoh [89] reported studies of the application of ion chromatography to the determination of fluoride, chloride, bromide, nitrite, nitrate, sulphate, sulphite and phosphate ions in 3 ml samples of rainwater. The results show that the most suitable eluent for this purpose is 2m mol L 1 sodium carbonate/5m mol L 1 sodium hydroxide. The reproducibility of the determination was satisfactory for standard solutions of all the ions except nitrite. This problem was solved by preparing standard and sample solutions with the same composition as the eluent. 

Sulphur dioxide, S02, and sulphurous acid H2S03 Sulphur dioxide gas, when dissolved in water, forms sulphurous acid. It is a strong reducing agent, its action is based on the transformation of sulphite ion to sulphate. The oxidation number of sulphur changes from +4 to +6, hence 2 electrons are released during the process ... 

In the classical case, R is sulphite and Ox sulphate. Three classes of related reactions have been recognised. To the first belong the sulphite, thiosulphate and stannous ion reactions, and with these (4) is always faster than (3) so that the starch-iodine colour emerges very suddenly when all the reductant is exhausted (by excess iodate). The second type can attain equal rates of iodine production, through (2) and (3), and decomposition (4). Starch-iodine colour is seen at about that point, with partial removal of the reductant e.g. arsenite, ferrocyanide, Fe(II) complexed with oxalate or EDTA). In the third type, reaction (3) is so much faster than (4) that the necessary iodide concentration to give starch-iodine colour is only attained late in reaction. Iodine is then present early but the blue colouration only develops later. A number of organic reductants fall into this class. The rates of colour development in the normal reaction system have been treated in semiquantitative fashion . ... 

Sulphur (S) occurs in soils usually as sulphites, sulphates, sulphides and in organic compoimds. However, the most accessible form is sulphate (SO ). The turbidimetric procedure is widely used in the estimation of available S in the soil due to its rapidity. However, erroneous results are obtained in case the soil is rich in organic matter. Soil is shaken with a solution of monocalcium phosphate, containing 500 ppm P. The phosphate ions displaces the adsorbed sulphate. The calcium ions depresses the extraction of soil organic matter, thus eliminating contamination from extractable organic S. The method extract soluble plus a fraction of adsorbed The filtrate is then analysed for S by the turbidimetric procedure. In this method... 

The tentative mechanism of isoprene transformation accompanying the autoxidation of S(TV) was suggested, which started with the addition of a sulphate radical to a double bond in isoprene, followed by addition of oxygen and formation of a peroxy radical. The peroxy radical reacted with sulphite ion to the alkoxy radical, which in turn reacted either with oxygen or with a sulphite ion to give respectively /rfl s-3-methyl-4-sulphoxy-2-buten-l-al or trctns-3-methyl-4-sulphoxy-2-buten-l-ol (Rudzinski e/a/., 2002 Rudzinski, 2004). 

Ledo de Medina, H., Gutierrez, E., Colina de Vargas, M., Gonzalez, G., Marin, J., and Andueza, E., Determination of phosphate and sulphite in natural waters in the presence of high sulphate concentrations by ion chromatography under isocratic conditions, J. Chromatogr. A, 739, 207-215, 1996. 

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