REVIEWS The object of this department of theyournal is to issue. as promptly as possible, ci-itical digests of allJourna1 articles that bear upon any phase ojPhysical Chemistry.
General Thermodynamics. K. WesendoncR. Wied. Ann. 69, 809 ('899). - A general discussion of the progress that has been made by investigators to fulfil the hope expressed by Clansius in 1867, that the second law of thermodynamics might be expressed in as simple and natural a way as the law of the conservation of energy. H . ir. B . Asymmetric nitrogen. J . A. Le Bel. Bey. chenz. Ges. Bedilc, 33, roo3 (1900). - The use of the culture method in the isolation of optically active compounds cannot be wholly dispensed with, as in many cases it is impossible to form crystalline compounds with active substances. The concentration at which the organism grows most abundantly must be first ascertained by experiment. At times a mycelium may form which does not attack one of the isomefs. Care must therefore be taken not to assume the absence of an asymmetric compound. Here traces of empyreumatic or aldehyde compounds are often sufficient to completely inhibit growth of the organism. The use of antiseptics, especially mercuric chloride, must be avoided. A temperature of 15'20' is the most favorable for fermentation, as at higher temperatures parasitic bacteria flourish which prey on the mould. C. G. L. W. The distillation of amalgams and the purification of mercury. G. A . Hzdetf. Zeit. phys. Chef%.33, 6zz (z9oo).-Mercury can be distilled without difficulty in a partial vacuum if air be let in as is done when distilling organic substances. Zinc and cadmium do not pass over with the mercury, but zinc oxid is carried over, probably mechanically, To test the purity of a sample of mercury, the author measures the electromotive force of a cell Zn I zinc salt, mercuric oxid I mercury. [It would be better to make this a zero method by using as the electrodes pure mercury and the mercury to be tested.] W. D.B. Revision of the atomic weight of iron. T. W. Richards and G. P.Baxfer. Zeit. anorg. Chem. 23, 245 (1900).- From the reduction of ferric oxid, the authors find 58.88 as a prelimiiiary value for the atomic weight of iron. W. D.B.
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Peruranic, permolybdanic, pertungstic, and the other corresponding acids. Zeit. anorg. Chem. 24, ro8 ((900). - Thermochemical D. B. measurements.
L . Pissarjewsky.
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One-Component Systems Density determinations of saturated vapors and liquids. R.F. von Nirsch. Wied. A n n . 69, 456 (2899).-By the method devised by Young, the relation of the volumes of a liquid and its vapor, in a closed tube at different temperatures up to the critical temperature, is studied for several organic substances. The results have led the author to speculate a little on the truemeaning of the critical temperature. The two curves of density and temperature for the liquid and vapor, or pressure and specific volume, have a common maximum or critical ” point, according to the ideas of Van der Waals, which the author considers does not really exist. On the contrary, he introduces the idea of a I * critical ” density as a third variable to the ‘ I critical ” temperature and critical ” pressure to explain the difference still apparently existing in the density of the saturation curve for liquid and gas at the critical ’’ temperature, or the temperature at which the meniscus disappears. The author further introduces the question whether a ‘‘ reduced ” or “ corrected ” equation of condition can really be said to exist. H . T. B. On the specific heat of metals a t low temperatures. U. Behn. Drude’s A n n . I, 257 ( ~ 9 0 0 )- .A continuation of the work by the same method used by the author previously ( 3 , 176) The metals Sb, Sn, Cd, Ag, Zn and Mg are studied together with graphite and several zinc and lead alloys. In all cases a decrease in specific heat with decreasing temperature was noted for observations at 1iso,oo, - 7 9 O , and --186‘, according to a parabolic law. Various tables are prepared and an attempt made to show the dependence of the specific heat on the relation of the atomic weight and atomic volume. H. T. B. On the heat of sublimation of CO, and the heat of vaporization of air. U. Rehn. Drude’s A n n . I, 270 ( 2 9 0 0 ) .- In the author’s previous work the mean specific heat of several of the metals is given between 18’ and - 7g0, and r 8 O and - 1 8 6 ~ . A method is here adopted for determining the heat of vaporization of air and the sublimation heat of CO, by introducing into a suitably protected vessel containing either of these substances a piece of metal of known weight and temperature, and thereby imparting a definite and known quantity of heat. This heat is used in either boiling the liquid air or in subliming the solid CO,. The amount of gas given off is collected and measured in a gasometer. A few sources of error are discussed and the methods adopted of avoiding them described, The result for air is found to be 50.8 calories, and for CO, 142.4 calories. By the aid of the results the density of air and CO, at ~-1 8 3 ~ and - 7 9 O is estimated. H. T. B.
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On adiabatic changes of condition of a system composed of a crystal and its melt, G. Tammanib. Duude’s A n n . I , 275 (1900).-The isentropic change of a crystal in equilibrium with its melt is shown to lead to the conclusion that the equilibrium is, in many cases, not greatly disturbed by the process, and that in view of this the principal thermal properties can be connected by simple equations. H. T. B.
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Measurement of low temperatures. A . Ladenbwg and C. KrCgel. Bev. ). apparatus of Holborn and W e n has chem. Ges. Berlin, 32, z8z8 ( ~ 8 9 9 -The been compared with the hydrogen thermometer at three points and the intervening points calculated by means of a cubic equation. This calculation was controlled by observing a fourth point. A large number of boiling-points and melting-points were observed. C. G . L . W. Measurement of low temperature. A. Ladenbnvg and C. x r u g e l . Bev. chem. Ges. Berlin, 33, 637 ( ~ 9 0 0 )-See . foregoing abstract. The boiling- and melting-points have heen re-examined. Differences of 1 ~ - 2 ' were found from C. G . L.W. those previously obtained. The hardness of simple substances. 1.R.Rydbeyg. Zeit. phys. Cltem. 33, 353 (1900). - It is shown that the hardness of the elements is a periodic function of the atomic weight. W. D. R. On a method for determining the inversion point of monotropic dimorphous substances. R.Schenck. Zeit. phys. Chenz. 33, 445 ( z 9 0 0 ) . -The author determines the relative pitch of the two curves for solid and vapor from the freezing-point constants, and then determiues, by extrapolation, the temperature at which these two curves would intersect. I n this way, a value of 105.9' is obtained for the inversion temperature with the two forms of wnitro-p-acettoluid in equilibrium. In the case of monochloracetic acid the two curves appeared to W. D.B. be parallel. The physical properties of cesium. M. Bckhardi and E. Graefe. Z e d . anorg. Cltem. 2 3 , 3 7 8 (1900).-The specific weight of liquid cesium at 27" is I .836, of solid cesium at 26' is 1.886. The melting-point is 26.3 j o ; the atomic heat is 6.406 ; and the heat of fusion is 3.73 cal. per gram. W. D. Iz.
Two-Component Systems The solubility of carbonic acid in alcohol between -67' and f4 5 O C ;invasion and evasion coefficients at 0 ' . C. Bohtr. Dvude's Ann. I , 244 (z900) . -Two methods are used to determine the solubility of CO, in alcohol ; one by saturating with the gas at different temperatures and finding the amount of dissolved CO, in a given quantity of alcohol, and the other more particularly for use at low temperatures, by determining the amount of gas given off on lowering the temperature of saturated alcohol from 0'. The measuremetits of the invasion aiid erasion coefficientsare made in a similar way to that described in the author's previous works ( 2 , 400 ; 4, 145). On comparing the results with water it is shown that the relatively large absorption coefficient of the alcohol for CO,, notwithstanding its evasion coefficient being nearly seven percent greater than for water, gives an invasion coefficient eighteen timesgreater than for water. Alcohol becomes much more quickly saturated with CO, so much so that if at oo the ratio of the surface to the volume be 1/5, then the same degree of saturation is reached in alcohol at the end of ten minutes, that is reached in water at the end of sixty-eight minutes. H. T.B.
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On compounds in alloys. N . S. Kurnakow. Zeit. anorg. Chem. 23, 439 (1900).-The freezing-point curve of sodium and mercury shows seven different solid phases capable of existing in equilibrium with solution and vapor above 0'. There is one temperature maximum corresponding to the composition NaHg,. Between Na and NaHg, there are four solid phases, three of which are probably solid solutions, while one appears to be NaHg. The solid phase appearing beyond the maximum temperature may be NaHg, or may not. The curve for potassium and mercury could not be determined close to the potassium end, but there is a maximum freezing-point at the composition KHg,. On the potassium side, the curve for this compound is terminated by the curve for a solid solution ; on the mercury side, there is evidence pointing to the existence of KHg,, after which come two solid phases, one of which may be KHg,,. With cadmium and sodium there is one maximum freezing-point at NaCd,, and another at about NaCd,. With sodium and lead there are two maxiina, one of which is not far from Na,Pb, while the other is distinctly not Na,Pb. With sodium and bismuth there is a maximum at Na,Bi. W. D.B.
A relationship between the specific heat of solutions of cobalt chlorid and 3 1 , z64 ((899).-Solutions of cobalt their color. M. Wresky. Jour. Russ. SOC. chlorid in aqueous alcohol were found to have a lighter color and smaller specific heat, the less the proportion of dissolved salt. Similar change of color and specific heat were brought about by lowering the temperature. C. E. L. On the specific heat of aqueous solutions of sulfuric acid. E . Biron. Jouv. concentrations varied from the monohydrate to one mol of the nionobydrate mixed with 1600 mols. of water. Full tables are given for the results obtained. The curve accompanying the paper shows that with increasing strength of the acid solution, its specific heat at first diminishes until at about 27 percent H,SO, it commenceb to increase, attaining a maximum in the neighborhood of 48 percent ; and then after falling off to the lowest value at about 86 percent, it attains a second (lower) maximum at about 95 percent. C. E . L .
Russ. SOC. 31, z7z (1899). -The
The hydrates of sulfuric acid. E. Biron. Jour. Russ.Soc.31,5z7(z899).Crystals were obtained whose composition corresponded to the formulae H,SO, (10.35~) ; H,SO,.H,O (8.53') ; H,SO,.zH,O (- 38.9') ; H,S04.4H,0 (- 29.0') ; the bracketed numbers are the melting-points of the crystals. C. E . L. On the freezing-point of aqueous solutions of non-electrolytes. E. H. Loomis. Phys. Rev. 9, 257; Zeit. phys. Chetn. 32,578 (1900).-In the earlier measurements the thermometer was kept completely packed in ice when not in Since the room temperature was about 5 O , it is clear that the stem of the thermometer had been supercooled and that the first measurements each day, those on the freezing-point of pure water, would necessarily be slightly wrong. The result of the most recent and the most accurate experiments is that the constant for aqueous solutions of propyl alcohol, butyl alcohol, amyl alcohol, glycerol, acetone, grape sugar, cane sugar, niannit, and anilin is 1.86 ; while it is 1.82 for methyl alcohol, 1.84 for ethyl alcohol, and r.50 for ether. The exceptions may be due to the volatility of the three substances. W. D.B . use.
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Solidification and inversion phenomena with optical antipodes. 1.AT. A d r i a n i . Zeit. phys. Chem. 33, 453 (1900).- Racemic compounds occur with dimethyl tartrate, dimethyl diacetyl tartrate, mandelic acid, and benzoyl tetrahydroquinaldin. All mixtures of the two camphor oximes freeze at the same temperature, I 1 8 . 8 O , the solid phase being a solid solution of the two antipodes. as is shown by the fact that the racemic compound is instable above 103'. With the two carvoximes, a continuous freezing point curve was obtained, passing through a maxinium at 91.4~.I t seems probable that, in this case, the solid phase consists of a solid solution of the racemic compound with one or the other of the components ; but there is no way of proving it a t present. W . D.B. The effect of pressure on the critical solution point. N. 1. van der Lee. Zeil. phys. t^hem. 33, 622 (1900).- Iucrease of pressure causes phenol and W . D . B. water to become less miscible.
Poly-Cotrzponent Systems Racemic compounds. I, SchZoJsbtirg. Bey. chem. Ges. Berliti, 33, 1082 investigation of double salts of racemic, pyrotartaric, tropaic and mandelic acids, according to the method of Roozeboom and Ladenburg, shows that in these compounds a racemic modification is present. C. G. L . W. (1900).-The
Active oxygen. C. Engler. Ber. chem. Ges. Beerlin, 33, io90 (1900).The absorption of oxygen by substances such as triethyl phosphin or benzaldehyde takes place in such a way that half of the oxygen-only will subsequently be given up to oxidize substances such as indigo or arsenious acid, while the other half remains with the '' autoxydator ". Although the existence of a compound belonging to the peroxid class has been shown by Engler and Weissberg (Ber. chem. Ges. Berlin, 31, 3c46 (1898)), a simi!ar behavior to the first mentioned substance has not as yet been proved. Titration of the active oxygen with stannous chlorid has not been found successful. The use of indigo sulfuric acid shows that the amount of oxygen given up by the turpentine is equal to very nearly fifty percent of the total absorbed. Direct estimation of the amount of oxygen absorbed by pinene shows that one molecule of theterpene absorbs between four and five molecules of oxygen. Experiments with unsaturated hydrocarbons, viz., amylene, trimethylene, ethylene, and hexylene, proved the absorption of a definite amount of oxygen by the compounds. In the case of amylene a certain part of the oxygen is used up to form a peroxid as the titration with stannous chlorid showed. A large number of unsaturated compounds, especially those of the allyl series, absorb oxygen, forming peroxids. In many cases the compounds act as direct oxygen carriers, bleaching indigo sulfuric acid in the presence of air. C. G. L . W. Active oxygen. C. Engler. Bel: chem. Ges. Berlin, 33, 1097 (r900).Van ' t Hoff has shown that atmospheric oxygen in certaiu oxidation processes is divided in its action. One-half goes to the directly oxidizable compound (autoxydator). The other half is combined with a compound which is not directly oxidizable (acceptor). According to van 't Hoff, the action is due to a certain amount of the gas being ionized into positive and negative oxygen of which the one is used up by the autoxydator while the other unites with the
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acceptor, No electric phenomena have so far been brought forward to support this view. The view of Engler and Wild may Le used to explain the facts in which the formation of peroxid is assumed, Hence the reaction processes in the following phases : A + 0, = AO, ; AO, B = A O + BO, where A represents e. g . triethylphosphin and B indigo sulfuric acid. A may also react instead of B giving A + 0, =AO, ; AO, A= A 0 AO. This is supported by the experiments of M. Franke on oxidation by molecular oxygen in the presence of water, where the formation of hydrogen peroxid is assumed to take place. The combustion of rubidium in air, by which only rubidium peroxid is formed is also in favor of this view. A number of interesting examples of oxidation in terpene, waxes, paraffins, oils, and resins is cited. I n those cases where quantitative methods have been used, it has been found that the oxygen taken up was double that required for a simple oxidation. In these cases, however, where an acceptor is present, the oxygen will be equally divided between it and the autoxj dator. This is to be seen in the formation of benzoylsuperoxid. The reaction is complicated by the formation of a superoxid hydrate. From consideration of autoxidation, the author comes to the following conclusions : I. Oxygen combines directly with unsaturated compounds forming peroxid. 11. Oxygen may combine with a labile hydrogen atom of the autoxydator forming hydrogen peroxid. The radical takes up another atom of oxygen forming a peroxid. 111. Oxygen may combine with a labile hydrogen atom of the autoxydator forming hydrogen peroxid. The radicle is not oxidizable and remains as such or double. The possibility is mentioned of the oxidation taking place with molecular oxygen and not with the element in the atomic state. The influence of light in oxidation may arise from increase in the active state of the molecule or may arise from a breaking of one of the bonds forming oxygen in the state .O.O. or 0 i 0, or perhaps that the oxygen dissolved in the autoxydator is rendered active by light. C. G. L . W.
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Active oxygen. C. Engler. Bur. chem. Ges. Berlin,' 33, zzo9 ('900). This paper is concerned with a demonstration of the formation of hydrogen peroxid and other peroxids as products of direct oxidation. Purified hydrogen is burned in air. The flame impinges against a piece of ice. Hydrogen peroxid may be recognized in the ice water by the usual tests. That the peroxid is not formed by direct oxidation of the water through the heat of the flame is proved by using a platinum wire raised to a white heat which is placed in ice water. No hydrogen peroxid is formed even after contact of the wire with the water for some hours. The formation of peroxids may be detected by a suitable arrangement of burning carbon monoxid, illuminating gas, alcohol, ether, and carbon biplfid. Sodium and magnesium also form peroxids which may readily be detected. C. G. L. W.
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Double metallic rhodanids. '4. Rosenheiin and R. Coheiz. Ber. chem. Ges. B e d i n , 33, zzzz (1900).- Salts of the type RHg(SCN), have been studied. They are in contradistinction to those of the type R,Hg( SCK), difficultly soluble in water. Conductivity-increase went to show that in both cases the anion consists of a rhodan mercury ion. Doublesalts of cobalt, nickel, and aluminium and chromium rhodanids with the alkalies and alkaline earths were prepared. In dilute alcoholic solution the cobalt is found as a part of the anion. I n the corresponding nickel salt, the nickel is found in the cation. C. G. L . W. Deduction of the reaction isotherm and isochore for dissociating mixtures. K. Ikedn. Zeit. phys. Chenz. 33, 287 (1900).-The chief novelty of the treatment consists in the assumption of two ideal non-miscible solvents, in one of which there is no dissociation, in the other of which there is complete dissociaD.B. tion.
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Change of solubility by salts. V. Rothmund. Z e d . phys. Chem. 33, 40z ( ~ 9 0 0 -The ). author finds that the solubility of phenyl sulfocarbamid in water is changed by the addition of salts, and that the percentage change does not vary perceptibly with the temperature between oo arid 40°' The author appears to think that he is opening up a new field. Without quite agreeing with this view, the reviewer is glad to learn that, in the author's opinion, the subject is of the greatest importance in working out a theory of solutions. W. D.B. Osmotic Pressure and D i f u s i o n
Simple deduction of van 't Hoff's law of osmotic pressure. K. Ikeda. Zeil. phys. Chem. 33, 280 (1900). - This is merely another way of deducing the van't Hoff formula. The original van 't Hoff deduction was straightforward, and enabled everyone to see what assumptions were made. The so-called improvements strive to make the formulas appear absolute, by masking the assumption. W. D.B. VeLocifies
On the constants of the speed of formation of simple ethers. W. Zagrebz'a. Jour. Russ. SOL.31, 19 ('899). -- The reaction studied was that of benzene sulfonic ethyl ether on methyl, ethyl, propyl, isobutyl, isoamyl, octyl, allyl, benzyl, isopropyl, and caproyl alcohols, and on tri-methyl and dimethethyl carbinols, the products being the corresponding ethers and benzene-sulfonic acid. The acid was titrated against 72/20 baryta water with phenol-phthalein as indicator. Equimolecular quantities of alcohol and benzene sulfonic ethyl ether when heated to IOOO separated into layers before the conipletion of the reaction, and the addition of a dilutent such as benzene, acetone, etc., did not help matters, as benzene-sulfonic acid is too insoluble in them. When, however, fifteen times as much alcohol as sulfonic ether were heated to IOO', the reaction was practically completed in a few hours. The comparison of the constants for the primary alcohols exhibits a fairly close parallelism with those obtained by Menschutkin for the compound ethers and amins, and the rule that the constant for tertiary alcohols are notably smaller than those for the primary and secondary alcohols are confirmed, although side-reactions seemed to interfere in the case of the tertiary alcohols. C. E. L.
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Some remarks on the subject of the investigation of the speed of formation of simple ethers. N. Menschulkin. Jour. Russ. SOC.31, a8 (1899). -Notes on Zagrebin’s work (preceding review) together with a program for future investigations along similar lines. C. E. L .
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Chemical kinetics and free energy of the reaction : 2HI zAg e zAgI + H,. H. Danneel. Zeit. Elektrochem., 6 , 293 (1899); Zeit. phys. Chew. 33, 415 (1.900).-Silver, silver iodid, and hydrogen are in equilibrium with aqueous hydriodic acid when the concentration of the latter is nio.042. From reaction velocity experiments, the author concludes that the hydrogen enters into the reaction as H, and not as H,. Attempts to confirm the equilibrium phenomena by electrometric measurements led to the unexpected result that good values are obtained when hydrogen is not made to bubble through the solution, while they are 0.02 V too high when this is done. W. D.B.
Electromotive Forces On the stationary temperature condition in an electrically keated conductor. I , r3z (‘900). -A new method is proposed for the purpose of studying the flow of heat in a long cylindrical metal rod heated by the passage of an electric current, and insulated thermally except at the two ends, which are maintained at a constant temperature. The position of the isothermal and isopotential surfaces are then transverse to the length of the rod. Only the theory of the method is treated of in the present paper, which should be taken in connection with the measurements of Jaeger and Diesselhorst, who have applied the method to the case of several metals and alloys. The author shows that the steady temperature condition does not depend on thermal or electrical conductivity alone, but on the ratio of the two. The pure metals form a group giving the smallest value of this ratio and at the same time the highest temperature. H. T. B.
F. Kohlffausch. D m d e ’ s Ann.
On the problem of an electrically heated conductor. H . Diesselhorst. Drude’s Ann. I, 3 r z (1990). -This is an extension of the paper by Kohlrausch in which he proposed and treated theoretically a new method for determining the ratio of the thermal and electrical conductivities in metals by the steady temperature condition set up in a metal bar heated by an electric current. The author treats the case of a change of conductivity with temperature, and also the Thomson effect, which has to be considered in using the method. A better form of this method was proposed by Callendar, and worked out by R. 0. King in 1898 and R. G. Duncan in 1899. n.T. B. Potential differences with manganese peroxid electrodes. 0. F. Tower. Zeit. phys. Chew. 32, 566 (1900).- Further measurements which do not add materially to our knowledge of the subject. W . D.B.
On decomposition points in aqueous solutions. A. Gockel. Zeit. phys. Chevz. 32, 607 (1900).- Measurements are published to show that there is no definite decomposition voltage, and that the point usually observed is that a t which there is visible precipitation, which may vary considerably with the con-
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ditions of the experiment. There is no doubt but that the absorption of gases and the roughness of surface is a factor. With the precipitation of metals, there is the further possibility that, a t given voltages, the metal may not have the properties of matter in mass, in which case the time element would vary with the size of the electrode. This side of the question is not brought out by the author, and, in other respects, one cannot congratulate him on the way he handles his experimental data. W. D.B. Reversible electrodes of t h i second class, with mixed depolarizers. A. Thiel. Zeit. anorg. Chem. 24, z (19oo).-The author has determined the electromotive force of silver covered with niixerl silver halids against the normal electrode. Silver chlorid and silver bromid form a continuous series of mix crystals and the potential varies continuously. Silver bromid and silver iodid form two series of mix crystals ; but the potential is practically that of silver bromid most of the way and then chaiiges rapidly to that of silver iodid. This is interesting, though not what one would have expected. D.B.
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Electrolysis and Ekctro!ytic Dissociation Conductivity of some sodium-substituted nitroparaffins. 0. Sulc. Zeit. phys. Chem. 32, 625 (1900). -The author has determined the conductivity of solutions of sodium nitromethane, sodiuni nitroethane, sodium nitropropane, sodium nitro.isopropane, and sodium nitro-isobutane. At a dilution of one thousand liters, the molecular conductivities lie between 80 and 109. W. D.B. On the hydrolysis of some chlorin compounds of platinum, gold and tin, caused by time or sunlight. F. Kohlrausch. Zeit. phys. Chew 33,257 (1900).An aqueous solution of H,PtCl,O undergoes almost no change in the dark ; in direct sunlight there is marked hydrolysis, as shown by the increase in conductivity. The acid H,PtCl, is hydrolyzed only in very dilute solutions. The acid H,AuCl,O is not affected by light ; the platinum electrodes cause precipitation of gold. Hydrolysis takes place in solutions of HAuC1,. An aqueous solution of SnCl, undergoes decomposition on standing, the change in the conductivity being proportional to the change in the logarithm of the time. W. D.B.
On electrolysis through semipermeable membranes. B. Moritz. Zeit. phys. Chem. 33, 513 (1900). -The author has investigated the behavior of membranes formed in parchment pape;. With the copper ferrocyanid membrane there is a precipitation of copper ferrocyanid so long as the polarization does not exceed 0.22 V. With ever higher potential differences there is first the formation of ferrocyanid as ion and then the precipitation of metallic copper. It is not certain whether this last phenomenon is or is not to be attributed to electrostenolysis. W. D.B. On the dissociation and dissociation equilibrium of strong electrolytes. H. Jahn. Zeit. phys. Chem. 33, 545 (‘900). -The author has determined the transference numbers of sodium, potassium, and hydrogen chlorids in dilute solutions. H e then measured the electromotive force of concentration cells with silver and silver chlorid as electrodes. Assuming complete dissociation in
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ai600 solution. and the accuracy of Nernst's formula for concentration cells, the
author calculates the dissociation in the other solutions. The values thus obtained are lower than those from the conductivity, and they follow the dilution law. The conclusion is therefore drawn that it is impossible to determine the degree of dissociation from the conductivity measurements, owing to the change of migration velocities with the concentration. W . D. B.
On the dependence of electric conductivity on pressure. G. Tainmarzn. Wied. Ann. 69, 767 (1899).-The author extends t h e previous work on t h e effect of pressure on t h e couducting power of dilute solutions, from 500 t o 3600 atmosphereq, in the case of sodium chlorid solutions and solutions of acetic acid. n, T. B. The analytical separation and detection of acids. R. Abegg and W. Herz. Zeit. n n o q . Chein. 23,236 (1900).- A n attempt has been made t o place in analytical groups the acids met most frequeutly in laboratory experience. Although it is evident that sufficient care has not been devoted t o t h e study of interfering reactions, the effort to p u t this analytical work on a systematic basis is worthy of commendation. There is no doubt that maiiy chemists will comply with the wishes of t h e authors that the nietliods be tried in IT. R.C. laboratories other than their o w n .
On the application of Faraday's law t o the electrolysis of fused salts. A. Helfensteiit. Zeit. anorg. Chem. 23, 255 ('900). -The author s h o n s t h a t i t is very difficult indeed t o get satisfactory quantitative results from the electrolysis of fused salts. The sources of error are the solubility and diffusion of metal and halogen, also the diffusion of t h e vapor of t h e metal. \\'hen these difficulties are eliminated, Faraday's law was shown t o hold. The interesting item in t h e paper is t h e surprising magnitude of the ' residual curW. n.B. r e n t ' when no precautions are taken. On some complex cyanids and sulfocyanates. P. Walden. ZeiL ano9.g. Chem. 23,373 ( 1 9 0 0 ) . -The author has determined the conductivity, a t different dilutions, of potassium silver cyanid, potassiuin mercuric cyanid, potassium zinc cyanid, potassium cadmium cyanid, potassium nickel cyanid, potassium platinic sulfocyanate, potassium cobalticyanid, potassium manW . D. 3. ganicyanid, and Ka,Fe( CN),NO. Electrosyntheses of diketones and ketones. N.Hofev. Be?,. chevn. Ges. Berlin, 3 3 , 650 (1900).-Acetoacetic acid and its salts arc not suitable for electrolysis on account of t h e ease with which they decompose. A solution of putassium pyruvate, elertrolj zed in t h e author's apparatus with potassium carbonate as t h e cathode electrolyte, gives diacetyl and acetic acid. Levulinic acid gives 2 . 7 octandin CHy.CO.CH,.CH,. A fifty perCH3.C0.CH,.CH, cent yield was obtained. Acetic acid is also produced in the reaction. A mixture of potassium pyruvate and acetate gives also diacetyl and acetone. With t h e potassium salts of pyruvic and butyric acids, methyl propyl ketone is produced. 1.5-Hexandion is formed i n the electrolysis of potassiuin pyruvate and levuliuate. The yield is small. I n all t h e reactions large quantities of gas were given off, consisting chiefly of carhon dioxid. C. G. L . W.
