Thiosulphate ions sulphate

The stoicheiometry and kinetics of reaction of aqueous ammonia solutions of copper(ii) ions with thiosulphate ion in the presence of oxygen have been examined. The amount of oxygen consumed and the relative amounts of the final sulphur products, namely trithionate and sulphate ions, are dependent on the initial 8203 concentration and pH. The most active species for SjOe" formation is a tetra-amminecopper(ii) complex having one axial 8303 and one axial O2 ligand. A complex having both axial and equatorial 8203 ligands as well as an axial O2 was suggested as the reactive intermediate for sulphate formation. 

Some coupled systems allow measurement of the main N and P forms (nitrate, ammonia and orthophosphates) [22,27,29], among which is a system based on membrane technology in combination with semi-micro continuous-flow analysis (pCFA) with classical colorimetry. With the same principle (classical colorimetry), another system [30] proposes the measurement of phosphate, iron and sulphate by flow-injection analysis (FIA). These systems are derived from laboratory procedures, as in a recent work [31] where capillary electrophoresis (CE) was used for the separation of inorganic and organic ions from waters in a pulp and paper process. Chloride, thiosulphate, sulphate, oxalate,... 

The said two ions partially oxidize thiosulphate to a higher oxidation form, such as sulphate (S042 ) thereby the stoichiometry achieved is always false. 

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]. 

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 . ... 

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... 

If now it is correct that only two of the four ions present are essential for complex coacervation (A and D) then an demixing must be able to occur even in the binary system HgO + AD. We have already met a single example (HgO + clupein sulphate, see p. 407). It is therefore important for the theory of complex coacervation to investigate if a similar demixing is realisable in the case in which both A and D are micro ions. Evidence for their existence (Sr molybdate, luteocobalti thiosulphate)... 

For the determination of copper, weigh out accurately about 0.5 g of your preparation into a conical flask. Add 30 cm dilute sulphuric acid and 2.5 g ammonium persulphate and shake well to dissolve the solids. Heat the solution gradually to the boiling point. Continue until all the copper appears as the blue copper(II) sulphate disregarding a small residue of sulphur which floats on the surface. Continue boiling for 15 minutes to decompose any remaining persulphate. Filter into a clean conical flask and wash on the filter with water. Add to the filtrate concentrated ammonia until the deep blue copper(lI) complex is formed. Ttien add dilute acetic acid to restore the pale blue colour of aqueous Cu(II) ions and then add an equal volume of the acid already added. Dissolve 2 g of KI and titrate the liberated iodine with standardised 0.05 M sodium diiosulphate until the solution is straw yellow. Dilute with 100 cm water, add 2 cm ficshly prepared starch solution and continue titration. When the blue colour fades add 1 g of purest ammonium thiocyanate and continue titration rapidly until the blue colour disappears for 1 minutes. The pale flesh-coloured Cul remains as a precipitate. Calculate the molar ratio Cu thiosulphate. 

---