Aqueous solution, hydrogen peroxide

In aqueous solution, hydrogen peroxide possesses only a very feeble electrical conductivity comparable with that of water, and cannot be regarded as an electrolyte.2 As a solvent, however, it exhibits certain characteristics similar to water thus it favours the dissociation of the solute, especially of acids, whilst with salts it tends to form compounds in a manner corresponding with the hydration of substances in aqueous solution3 (p. 333). The absorption spectrum of hydrogen peroxide for ultra-violet light has been examined.4... 

Photosynthetic Production of H2 and H2O2 on Semiconducting Oxide Grains in Aqueous Solutions Hydrogen peroxide formation observed in Ti02 powder suspensions as in Ref. 243 for Ti02 fdms. 248... 

Homogeneous aqueous solution, hydrogen peroxide decomposition in, 4, 31... 

In aqueous solutions, hydrogen peroxide can oxidize or reduce a variety of inorganic ions. When it acts as a reducing agent, oxygen gas is also produced. 

Finally, the hydrazide 29 98> is strongly fluorescent in neutral solution (e.g. in dioxane), the fluorescence intensity amounting to about 200% of that of 7-dimethylamino-naphthalene-1.2 dicarboxylic hydrazide 30, which is one of the best chemiluminescent hydrazides 97b The 5-isomer, however, is very poor in chemiluminescence in an aqueous system (hemin-catalyzed oxidation with aqueous alkaline hydrogen peroxide), the light yield being only 1 % of that of the 7-isomer in DMSO/t-Bu0K/02 its quantum yield is slightly better but very distinctly below that of 30 98>">. It should be mentioned that in aqueous alkaline solu-... 

Pure 2-propanol was at its natural pH. Similar results were obtained for aqueous solutions at natural pH and using phosphate buffer to give pH = 6.98. In alkaline solution, hydrogen peroxide solutions are unstable and could not be measured accurately, but G(H202) — 3.5 at all concentrations. 

A variety of peroxo and hydroperoxo complexes of zirconium(IV) and hafnium(IV) have been isolated from aqueous or aqueous methanolic hydrogen peroxide solutions that contain additional ligands such as sulfate, oxalate or fluoride. Examples of recently reported complexes are listed in Table 8 along with characteristic vibrational frequencies and the pH employed in the aqueous preparations. Earlier work on peroxo compounds has been reviewed by Connor and Ebsworth180 and by Larsen.5... 

UHP can be represented by the structure in Figure 2.7. UHP is readily crystallized from aqueous strong hydrogen peroxide and urea solutions.5 Being an anhydrous essentially neutral complex, it is a convenient alternative to very highly concentrated hydrogen peroxide (> 85% m/m), which is difficult to obtain and relatively hazardous. 

Addition of the micelle-forming cetyltrimethylammoniumbromide (CTAB) to solutions of 3-monoalkylamino phthalhydrazides (27) - (30) in aqueous alkaline hydrogen peroxide/potassium persulfate [42 b, 45]... 

In the laboratory, hydrogen peroxide can be prepared in dilute aqueous solution by adding barium peroxide to ice-cold dilute sulphuric acid ... 

Hydrogen peroxide is obtained in aqueous solution at the bottom of the column. This is a good method of preparation. 

The ammonium hydrogensulphate is returned to the electrolytic cell. A process such as this yields an aqueous solution containing about 30% hydrogen peroxide. The solution can be further concentrated, yielding ultimately pure hydrogen peroxide, by fractional distillation but the heating of concentrated hydrogen peroxide solutions requires care (see below). 

Because of the instability of pure and concentrated aqueous solutions of hydrogen peroxide, it is usually used in dilute solution. The concentration of such solutions is often expressed in terms of the volume of oxygen evolved when the solution decomposes ... 

Aqueous solutions of hydrogen peroxide decompose slowly the decomposition is catalysed by alkalis, by light and by heterogeneous catalysts, for example dust, platinum black and manganese... 

Hydrogen peroxide in aqueous solution is a weak dibasic aeid the dissociation constant for H2O2 — -1- HO2 is 2.4 x 10 ... 

Hydrogen peroxide in aqueous solution has many uses, because the products from its reaction are either water or oxygen, which are generally innocuous. The chief use is bleaching of textiles, both natural and synthetic, and of wood pulp for paper. Other uses are the oxidation of dyestuffs, in photography and in the production of... 

In what way does a solution of hydrogen peroxide react with (a) chlorine water, (b) potassium permanganate solution, (c) potassium dichromate solution, (d) hydrogen sulphide 50 cm of an aqueous solution of hydrogen peroxide were treated with an excess of potassium iodide and dilute sulphuric acid the liberated iodine was titrated with 0.1 M sodium thiosulphate solution and 20.0 cm were required. Calculate the concentration of the hydrogen peroxide solution in g 1" ... 

Aqueous solutions containing titanium(IV) give an orange-yellow colour on addition of hydrogen peroxide the colour is due to the formation of peroxo-titanium complexes, but the exact nature of these is not known. 

B). Many nitriles when treated with hydrogen peroxide in warm alkaline solution undergo hydrolysis to amides which can thus be readily obtained in high yield. Insoluble liquid nitriles can be treated directly in the aqueous suspension, but for insoluble solid nitriles the addition of a suitable organic solvent to give a complete solution may be desirable, although the completion of the hydrolysis may not then be so readily detected. 

Method(B). Add3g. (3ml.)ofbenzonitrileto50ml.of lo-volumes hydrogen peroxide in a beaker, stir mechanically and add i ml. of 10% aqueous sodium hydroxide solution. Warm the stirred mixture at 40° until the oily suspension of the nitrile has been completely replaced by the crystalline benzamide (45-60 minutes). Cool the solution until crystallisation of the benzamide is complete, and then filter at the pump and recrystallise as above. One recrystallisation gives the pure benza-mide, m.p. 129-130° yield of purified material, 2-2-5 S ... 

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