View Article Online / Journal Homepage / Table of Contents for this issue 10 ABSTRACTS OF CHEMICAL PAPERS. lnorganic Chemistry. Reactions of Hydrogen Peroxide. By ARNOLDNABL (Moncctsh., 1901, 22, 737-744. Compare Abstr., 1901, ii, 16, 94)-Hydrogen peroxide and sodium thiosulphate react according to the equation : Published on 01 January 1902. Downloaded 25/10/2014 22:04:43. 2Naj2S20,+ H202= 2NaOH + 2Na,S40,. If the alkali is not neutralised, 75 per cent. of the thiosulphate remains unoxidised and the reaction leads to the formation of sulphate and dithionate as well as tetrathion- ate : 2Na2S20,+ 7H202= 2Na2S04+ H2S206+ 6H20j H2S206+ H202= 2H,SO,. Barium sulphite and hydrogen peroxide give a small quantity of dithionate as well as of sulphate when the sulphite is in excess, The reactions represented by the equations 2H2S0, + H202= 2H,O + H2S206 and H2S206+ H202= 2H2S04,therefore take place simultaneously. K. J. P. 0. Alkali Salts of Hydrogen Peroxide in Aqueous Solution. By HARRYT. CALVERT(Zeit. physikal. Chem., 1901, 38, 513-542)- An historical account of the peroxides of the alkali metals is given. For the experiments, the hydrogen peroxide was prepared by repeated distillation until the conductivity was constant, and then concentrated on the water-bath. The distribution ratio of hydrogen peroxide between water and ether at 20' is 15.6 and is independent of the con- centration. A constant ratio (7.03 at 25*, and 6.65 at 0') was also found when the ether was replaced by amyl alcohol, and this is not altered by the addition of acids, In presence of alkalis, the distribu- View Article Online INORGANIC CHEMISTRY. 11 tion ratio is increased and the curve representing the change of ratio with increasing concentration of hydrogen peroxide approaches asymptotically to a line denoting the ratio on the assumption that 1 mol. of alkali fixes 14 mols. of hydrogen peroxide. Addition of hydrogen peroxide diminishes the saponifying power of sodium hydroxide, indicating that hydroxyl ions disappear. The conductivity of hydrogen peroxide solutions was determined in a modified Kohlrausch cell, in which the electrodes consisted of tinned iron, which does not catalyse the solution. The conductivity of alkali salt solutions is very slightly diminished by addition of hydrogen peroxide ; that of solutions of hydroxides of the alkali metals is very greatly reduced, This is explained on the assumption t'hat with the -hydroxyl ions tke hydrogen peroxide forms superoxide ions, the migration-velocity of which is small compared with that of the hydroxyl ions. Using the Ostwald-Walden rule, the author calculates the migration-velocity of this new anion to be 48.5 (Kohlrausch and Holborn units), the same value being found from solutions containing the cations Li., Na*, K*,Rb*, and Cs*. The migration of the superoxide anion has been proved experi- mentally by the method described by Noyes and Blanchard (Abstr., 1901, ii, 91), lead oxide being used as indicator. From the depression of the freezing point of water containing sodium hydroxide and hydrogen peroxide, using excess of the latter to diminish the hydrolysis, it is shown that the anion is univalent and is derived from the liydroxyl ion and neutral hydrogen peroxide (Abegg and Bodlander, Abstr., 1899, ii, 542). The results are in agreement with the assumption that the ion is O', and the compound formed from sodium hydroxide and hydrogen peroxide is NaO,. The solubility of potassium chlorate in hydrogen peroxide is much greater than that in pure water, and consequently such a determination Published on 01 January 1902. Downloaded 25/10/2014 22:04:43. could not be used to ascertain if the hydrogen peroxide forms a com- plexion with the cation. J. McC. Molecular Compounds of Hydrogen Peroxide with Salts, By SIMEONL. TANATAR(Zeit. anorg. Chem., 1901, 28, 255-257).- The compound KF,H,O, is obtained by dissolving potassium fluoride in 15 per cent. hydrogen peroxide and evaporating at 5OOso long as no serious decomposition occurs. It crystallises in monoclinic needles, is not hygroscopic, but exceedingly soluble in water, is not decomposed at 70" and only partially so at llOo, and is fairly stable when dry. A similar compound is obtained by dissolving sodium sulphate in 3 per cent. hydrogen peroxide and has the composition Na2S0,, 9H,0,H20,. With sodium nitrate, the double salt, NaNO,,Na,O,,SH,O, is obtained. It is very unstable. E. C. R. Generalisations on Halogeln Double Saits. By HORACEL. WELLS(Amer. Chem. J., 1901, 26, 389--408).-A long list is given of halogen double salts of the alkali metals, ammonium, and univalent thallium, with negative metals ; the salts are arranged according to types, which are designated by ratios indicating the number of atoms of each metal present. View Article Online 12 ABSTRACTS OF CHEMICAL PAPERS. The remarkable similarity in the prominent types of the series of different valencies leads to the conclusion that the valency of the metal of a negative haloid has no influence on the types of double salts which it forms. The molecules of alkali haloids have nearly the same combining power as molecules of negative haloids. Salts of simple types (particularly the 2 : 1 and 1 : 1 ratios) predomi- nate. Remsen’s law which states that the number of alkali haloid molecules which can combine with a negative haloid molecule is not greater than the valency of the metal of the latter, must be aban- doned. The double haloids appear to increase in variety and ease of formation from the iodides to the fluorides. They may be classified in three groups, based upon their behaviour in solution. (1) Salts, such as potassium platinichloride, which undergo ionisstion into alkali metal ions and complex negative ions. (2) Salts which readily separate into their component haloids in solution, but can be recryst,al- lised unchanged from water or from dilute acid solutions. (3) Salts which require the presence of an excess of one of their component haloids in solution for their formation. E. G. Tri-iodides. By YUKICHIOSAKA (Zeit. yhysikal. Chem., 1901, 38, 743--749).--The addition of iodine to a solution of potassium iodide or hydrogen iodide produces a rise of the freezing point proportional to the quantity of iodine added, and greater for the hydrogen than for the potassium salt. Hence it follows that the total concentration of ions and undissociated molecules is decreased by the addition of iodine. This necessitates a greater affinity constant for the iodides than for the tri-iodides, so that Damson’s assumption that these affinity constants are equal is incorrect (Trans., 1901, 70,238). L. M. J. Influence of the Concentration of the Hydrogen Ions on Published on 01 January 1902. Downloaded 25/10/2014 22:04:43. the Action of Iodates on Haloid Salts. By HUGODITZ and B. M. MARGOSGHES(Zeit. angew. Chem., 1901, 14, 1082-1091).- Potassium iodate and iodide readily react in the presence of a sniall amount of an acid (hydrogen ions) liberating iodine, and the amount thus deposited is directly proportional to the amount of acid present (Fessel, Zeit. anorg. Chem., 1900, 23, 66). Potassium bromide and iodate do not react so readily in the presence of an acid (Bugarszky, Abstr., 1896, ii, 216) and the iodine ions are only transformed into free iodine when the concentration of the hydrogen ions exceeds a certain minimum. Potassium chloride reacts less readily than the bromide and the necessary concentration of hydrogen ions is much greater. When definite amounts of hydrochloric or sulphuric acid are zdded to a potassium iodide solution mixed with an excess of iodate, the amounts of iodine liberated and of iodate left are found to corre- spond with t8he amounts required for the given quantities of acid employed. The free iodine was extracted with toluene and titrated with N/lO thiosulphate and the residual iodate was titrated by means of the same reagent. When acetic acid is added to a potassium iodide-iodate mixture, the reaction is not normal and the residual iodat,e is always less than that required by theory j similar results View Article Online INORGANIC CHEMISTRY. 13 have been obtained when acetic acid was used in presence of sodium acetate. The anomaly is probably due to the formation of an organic kiYl%Tl3 uijva i?ig-6, Boric acid is not capable of liberating iodine from an iodide-iodate mixture except in the presence of glycerol or dextrose. The same acid does not liberate free halogen from a bromide-iodate mixture, wen in the presence of glycerol. Phenol also is incapable of liberat- ing iodine, but picric acid liberates a small amount from an iodide- iodate mixture. With mixtures of bromide, iodide, and iodate in the presence of acetic or hydrochloric acid, the amount of iodine liberated corresponds with the reaction between the iodide and iodate. A bromate-iodide mixture also yields iodine on treatment with acids, but requires the addition of several C.C. of N/lO acid before the liberation of iodide is started. A bromide-bromate mixture in the presence of acetic acid and. sodium acetate yields no free halogen. A chlorate-iodide solution, even in the presence of considerable! excess of dilute hydrochloric acid liberates but little iodine ; coneen-- trated acid, on the contrary, liberates a much larger amount. J. J. S. Supposed Anomalous Behaviour of Oxygen at Low Pres- sure. By MAXTHIESEN (Ann. Phys., 1901, [iv], 6, 280-301).-Tht? author's observations are quite unfavourable to the supposed existenc6: of an anomaly for oxygen under 0.7 mm. pressure (compare Bohr, Ann. Yhys. Chern., 1886, [ii], 27, 459; Eayleigh, Abstr., 1901, ii, 542). J. C. P. Dissociating Power of Hydrogen Sulphide. By WM. T. Published on 01 January 1902.