Poly. Component Systems T h e theory of fractional precipitation of neutral salts and its application in analytical chemistry. A.Findlay. Zeit. phys. Chent. 34, l a y (zyoo). - The author points out that where two sparingly soluble salts may be forriied, it is not necessarily the least soluh!e which precipitates first, the relative concentrations being also an important factor. T h e author then studied the reversible equilibrium PbSO, 4 2 N a I h q
PbI,
-
?Ja,SO,.
\\‘hen lead sulphate and iodide are present as solid phases, the concentration of sulphate as ion should be proportional to the square of the concentration of iodine as ion. This was found to be very nearly true. T h e equilibrium constant was also determined electrometrically, though not with great accuracy. The author completed his research by adding lead nitrate to the solution.
1v.1). c.
On the behavior of ammonia toward salts in aqueous solutio?. D .Kmown/of, Jour-. X’uss. SOC.3 1 , yS5 [ / S p y ) . -The conclusions arrived at are these : I . Ammonia in aqueous solutions forms, with salts of silver, copper. zinc, and cadmium, definite cornpounds corresponding to the general formula,SzmNH,,. where 111 is the equivalent of the metal entering into the composition of the salt S. 2 . T h e formation of these compounds arises from substitutions for hydrate water and can serve as most excellent indirect proof of the existence of hydrates of salts in solution. 3. The changes of the pressure of ammonia in solutions of the saltsof alkaline and the alkaline-earth metals are subject to an additive law ; for a n increase in strength of the acid entering into the composition of the salt, the solubility of the ammonia becomes greater, while for a n increase in the strength of the base, it becomes srnaller. j.The changes of solubility both of the salts and the anitnonia may be explained according to the physico-chemical theory of solutions. j . The theory of electrolytic dissociation is insufficient to account for the abnorrrially large values of the osmotic pressure. 6. The values of the osmotic pressure determine the condition of the solvent in the solutioii, and for the cases of abnormally large values, we find evidence of chetnical action between the solvent and the dissolved substance. j . T h e physico-cheniical theory of solutions agrees with the theory of liq uid s . S. The relationship between the values of the maximum molecular electrical condactivity and the electrical condnctivity a t a given concentration can serve to characterize the degree of hydration : the electrical conductivity depends upo’n the relative strengths of the acids and the base. c.E . L .
On the absorption of nitrogen and hydrogen in aqueous soliitions of different . acid substances. L. Ei-nurt. Zeit. phys. Cheti~.33, 721 ( ~ y o o )-Propionic appears to have no effect o n the solubility of nitrogen or hydrogen in water, a t any rate u p to nornial solutions. The presence of urea does change the ab-
sorption coefficient of nitrogen and no experiments were made with hydrogen. T h e author points with pride to these results as showing that the solubility of a gas is not a function of t h e concentration in the solution of a non-electrolyte. Sodium chloride and hariuni chloride both affect the solubilitJ-, the change in the absorption coefficient being proportional to the two-thirds power of the concentration. Here again, the author is most impressed by the fact that there is zero disturbance for zero concentration. W . 11. E .
On the want of uniformity in the action of copper-zinc alloys on nitric acid. Glndsfoite. Phil. .l/nr. [j]5 0 , 231 f 1 9 0 0 ) . -Experiments are pub-
f. H .
lished, showing that the decomposition-products formed when nitric acid acts on a zinc-copper alloy or a corresponding niixture may. and sometimes do, differ w r y considerably, so that n o conclusion as to the heat of formation of the alloys can he deduced from such experiments. II’. ZI R. The double nitrates of tetravalent cerium and thorium. R.f.A?Ttg~ei. nitd Bey. cheut. Ges. Bediv, 33, 2135 ( 1 9 0 0 1. -The authors have prepared the basic nitrate of ceriuni in a crystalline condition. Cerium, ruhidiuni, :md caesium form double nitrates with ammonium and potassium which have been analyzed. Thorium forms salts corresponding to the types, ThR’( S O : , )i, gH,O ; ThR’,(NO,),, : ThR,,ISO:,),,.SH,O. The potassium salt is peculiar. I t has the formula ThK,H,( SO:,),,.gH,O, and forms spendid plates. G. L . ll’.
R.Jacoby.
c.
Commercial thorium nitrate. W.A’lTu/h~izni//~ nizi! E . Bnrrei,. Krr. chem. Ges. Berlin. 33, 2028 ( 1 9 0 0 ) . - T o prepare pure thorium compounds the authors fractionate with potassium chromate. Gadolinium and yttrium are only precipitated after the thorium compound is completely thrown out of solution as t h e chromate. The thorium nitrate was mixed with the requisite quantity of cerium nitrate and the incandescent value of the mixture deterniined. T h e mixture gave a siightly greater value than certain commercial sorts. The salts of didymium and yttriuni are detrimental to the lighting value of thorium nitrate, whereas the impurities found in conimercial cerium, riz. neodymium and lanthanum d o not appear to affect the qualities of the mantle. The .luer mixture is viewed as a solid saturated solution of cerium oxide in thorium oxide (o.g’%,). IVhen the cerium oxide is above this amount it acts as a foreign substance and as such reduces the value of the niixture. ~
C. G. L. E’ The action of permanganate solutions on hydrogen peroxide and on Caro’s reagent. A. Bneyrr n?id I?. 17iflirer. Bel- dieiu. Ges. Berlin, 33, 2488 ( 1 9 0 0 ) . - T h e reduc:ioii of permanganate b y the action of hydrogen peroxide is not due t o the formation of a trioxide of hydrogen. Oxygen gas is set free, and t h e non-appearance of the gas in former experinieiits is due to supersatnration of the solution with the gas. I n the action of permanganate on sulphomonoperacid (Caro’s reagent), hydrogen tetroxide is not formed. I n a pure condition these two reagents d o not act on one another. Caro’s acid decomposes spontaneously into sulphuric acid and hydrogen peroxide. The latter reduces a small quantity of the permanganic acid into manganous sulphate,
