Equivalents Of Chlorine Research Articles

V. The atomic weight of chlorine: An attempt to determine the equivalent of chlorine by direct burning with hydrogen

Some apology seems needed in presenting a new research on the atomic weight of an element already measured with a precision which the highest living critic has emphasised as “the magnificent accuracy of Stas’ determination." Moreover, the present experiments cannot claim an accuracy to be compared with any individual series of Stas’ ratios. But, on the other hand, Stas’ atomic weight of chlorine is derived indirectly from oxygen by a series of operations which include the determination of (1) the oxygen in potassium chlorate, (2) the silver equivalent to the molecule of potassium chloride, and (3) the composition of silver chloride. Stas himself has assigned different values to these ratios at different times; e. g ., in 1860 he found that 100 parts of silver were equal to 69·103 of potassium chloride, in 1882 he found 100 of silver equal to 69·119, and in his latest work to 69·123 of potassium chloride. Therefore, although Stas’ value 35·457 (O = 16) is in satisfactory agreement with Clarke’s value 35·447 re-calculated from all the best determinations, it is possible that some constant error may occur in some part of the long chain connecting the value of hydrogen with that of chlorine, an error which would be repeated from link to link., and would become evident only when the two ends of the chain were connected up. A direct comparison between hydrogen and chlorine might not only serve to detect any systematic error in this chain of ratios, but such a comparison, inasmuch as it does not involve the probable error of other ratios, would be cœteris paribus more exact. Again, the closing of the chain between hydrogen and chlorine with reasonable accuracy would permit the accidental errors to be distributed and prevent their accumulation at the unconnected end. The accumulated “probable error” in Clarke’s recalculated value for chlorine is ±·0048; the “probable error” of our nine experiments is ±·0019.

The atomic weight of chlorine: an attempt to determine the equivalent of chlorine by direct burning with hydrogen

Although the atomic weight of chlorine has been determined by Stas and other chemists with extraordinary care, nevertheless owing to the very indirect methods hitherto used in making the comparison between chlorine and hydrogen, it is possible that a, constant error may occur in some link of the long chain of connecting ratios. To join up the open ends of the chain by a direct comparison between chlorine and hydrogen, if it could be done with reasonable accuracy, would serve not only to detect any such systematic error, but would permit the accidental errors to be distributed and prevent their accumulation at the unconnected end. According to Professor F. W. Clarke the accumulated “probable error” in his recalculated value for chlorine amounts to ±0·0048; the probable error of the mean of our nine determina­tions is less than ±0·002. It was at the suggestion of Professor E. W. Morley, of Cleveland, U. S. A., that we have attempted this direct comparison by determining the weight of hydrogen which burns in a known weight of chlorine.

XII. On fluoride of silver. —Part II

On account of the prospect of being able to isolate fluorine by means of the action of chlorine, bromine, or iodine on argentic fluoride, I have in this investigation very fully examined the behaviour of those substances with that compound. Behaviour with Chlorine (continued). —To ascertain more completely the nature of the compound formed by fluoride of silver with chlorine and platinum at a red heat, I passed a very slow current of pure chlorine over 24.62 grains of argentic fluoride in a platinum boat within a 20-inch platinum tube during nine hours at a very low red heat. A very minute amount of a vapour which corroded glass was continually evolved ; and traces of a sublimate occurred, consisting chiefly of argentic chloride. On heating the boat and tube to redness after the experiment, a boiling sound was heard, a little fume and much chlorine escaped, and a loss of weight of 11.70 grains took place. On weighing the cooled apparatus a gain of 6.49 grains upon the original weight still remained, theory requiring 6.88 grains if the whole of the fluoride took up its equivalent of chlorine with­ out any fluorine being expelled. The thick platinum boat was powerfully corroded, and immoveably fixed to the tube, even at a red heat. The residuary salt was easily fusible, tasteless, of a dark red colour, and contained much combined platinum ; 3.38 grains of it fused with alkaline carbonates yielded 2.56 grains of metal (theory requiring 2.51 grains), of which by analysis 1.82 grain was found to be silver, and .74 grain was platinum: .63 grain of chlorine was also found in it, showing that the chlorine in it was chemically equivalent in amount to the silver. The deficiency of .19 grain required to make up the quantity taken I have set down as fluorine. The red salt corroded glass in the presence of damp air, and contained only a few very minute particles of platinum.

V. Notes of researches on the poly-ammonias.—No. V. Action of bichloride of carbon on aniline

In two former notes I have described the deportment of aniline as the prototype of primary monamines with the bromine- and chlorine-compounds of biatomic and triatomic radicals. It was found that under the influence of these agents, two equivalents of aniline coalesce to a more complex molecule, retaining the chemical character of the constituents; the action of bibromide of ethylene and chloroform producing respectively— Diethylene-diphenyl-diamine …...C 32 H 18 N 2 = { (C 4 H 4 ) 2 '' (C 12 H 5 ) 2 } N 2 . Formyl-diphenyl-diamine.....C 26 H 12 N 2 = { (C 2 H)''' (C 12 H 5 ) 2 H } N 2 . The result of these experiments led me to examine the behaviour of aniline under the influence of organic chlorides containing even a larger number of chlorine equivalents. The agent selected was the body well known by the name of bichloride of carbon, i. e . tetrachlorinetted marsh-gas, or chloroform, in which the residuary equivalent of hydrogen is replaced by chlorine.

II. On the bromide of titanium

A comparison of the boiling-points of corresponding chlorine and bromine compounds, led Prof. Kopp to the interesting discovery, that on the average their boiling-points rise 32° C for every equivalent of bromine which is substituted for an equivalent of chlorine. Boiling point. Difference. Chloride of ethyl, C 4 H 5 Cl . . . 11° C. Bromide of ethyl, C 4 H 5 Br . . . 41° C. } 30.

On the chemical nature of wax.―Part III. On myricine

This paper is the last of three papers on the chemical nature of wax, and contains the investigation of that portion of bees-wax which is soluble only with difficulty in boiling alcohol. This body could never be rightly investigated before the discovery of the true nature of the other constituent of the wax, namely, the cerotic acid, for the absence of which no test was known, and the products of the decomposition of which would materially interfere with any experiments on the nature of the myricine. When the cerotic acid has been absolutely removed by repeated boiling of the wax with alcohol, a substance remains, which is saponifiable, but with difficulty. From the products of saponification the author isolated palmitic acid, C 32 H 32 O 4 , and a. new wax-alcohol, analogous to, but yet different from cerotine, described in a former paper. This alcohol, melissine, has the formula C 60 H 02 O 4 . By oxidation of this substance by means of lime and potash, the acid C 60 H 60 O, melissic acid, was obtained; and by the action of chlorine, a body analogous to chloral, a substance, that is, of the aldehyde series, but with a substitution of between fourteen and fifteen equivalents of chlorine for hydrogen. In its conversion into this substance the alcohol loses two equivalents of hydrogen, without substitution. The author also investigated the products of the distillation of myricine. From these he procured likewise palmitic acid and a solid hydrocarbon, which, rectified over potassium, had a melting-point of 62°, and contained, as shown by analysis, carbon and hydrogen in equal equivalents. The analogy of the mode of formation of this substance to cerotine from Chinese wax shows that it is the hydrocarbon, melene, C 60 H 60 . By repeated crystallization from ether a substance was obtained from the impure myricine, of a crystalline character, melting at 72°; the analysis of which agrees with the formula C 92 H 92 O 4 , which explains the reactions of the substance. The general conclusion from this investigation is, that waxes are a class of bodies which, chemically speaking, stand in the same relation to fat as fatty bodies do to the alcohol and acetic acid of vinous fermentation; all which bodies are members of one chemical series, possess an analogous chemical character, and are susceptible of analogous transformations.

Equivalent of chlorine

"Equivalent of chlorine." The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 28(190), p. 566

On the application of the conversion of chlorates and nitrates into chlorides, and of chlorides into nitrates, to the determination of several equivalent numbers

The researches which form the subject of this paper were suggested by an inquiry into the most effectual method of ascertaining the quantity of nitrate of potassa existing in crude saltpetre. The author found that by the action of hydrochloric acid the nitrate of potassa was converted into the chloride of potassium; and conversely, that the chloride of potassium might, by the proper regulation of the temperature, be reconverted into the nitrate of potassa by the action of nitric acid. These mutual conversions afforded excellent means of determining, with great exactness, the relative equivalent numbers, in the theory of definite proportions, belonging to these salts, and to their respective constituent elements. The author, accordingly, pursued the investigation of these numbers by several successive steps, of which the details occupy the greater part of the present paper. He first determines the equivalent of chloride of potassium by decomposing chlorate of potassa into oxygen and chloride of potassium; the proportion between which gives the ratio which the respective equivalent numbers of each hear to one another, and also to that of chlorate of potassa. The equivalent of nitrate of potassa is next obtained by converting the chlorate and the chloride of potassium into that salt; and from these data the equivalents of chlorine and of nitrogen are deduced. A similar train of inquiry is next instituted with the corresponding salts having sodium for their base: chlorate of soda being decomposed into the chloride, and into the nitrate; nitrate of soda into chloride; and chloride of sodium into nitrate of soda. The results of these different series of experiments coincide so closely with one another as mutually to confirm their general accuracy in the most satisfactory manner. For the purpose of determining the equivalent numbers of the elementary bodies themselves, (namely, chlorine, nitrogen, potassium, and sodium,) the author employed the intermedium of silver, the several saline combinations of which with chlorine and with nitric acid were found to afford peculiar advantages for the accurate determination of the relative weights of the constituents of these salts, when subjected to various combinations and decompositions. The conclusions to which the author arrives with regard to the equivalent numbers for the six elementary bodies in question, tend to corroborate the views of the late Dr. Turner, and to overturn the favourite hypothesis that all equivalent numbers are simple multiples of that for hydrogen. He finds these numbers to be as follow: Oxygen 8· Chlorine 35·45 Nitrogen 14·02 Potassium 39·08 Sodium 23·05 Silver 107·97 The author intends to pursue these inquiries, by applying similar methods to the investigation of other classes of salts.

On the composition of chloride of barium

The frequent employment of chloride of barium in delicate chemi­cal investigations, renders an exact knowledge of its composition pe­culiarly desirable ; and this has become a more important object of inquiry since it has been made by Dr. Thomson the basis of his calcu­lations of the chemical equivalents of sulphuric acid, and of thirteen metals and their protoxides. He has deduced from his experiments with the chloride of barium the number 36 as the equivalent of chlorine ; 70 as that of barium; and 78 as that of baryta; whence the equivalent of the chloride of barium would be 106 ; and accord­ingly, on mixing this quantity of the chloride with 88 parts of sul­phate of potash, each being previously dissolved in separate portions of distilled water, he finds a complete double decomposition has taken place ; the resulting sulphate of baryta, reduced to dryness, weigh­ing 118 parts, and the muriate of potash yielding 76 parts of chlo­ride of potassium. Hence he infers that 40 is the equivalent number for sulphuric acid, and 48 that for potash. Berzelius, however, maintained that this experiment, as well as the deductions from it, are not exact. Dr. Thomson having, in consequence of Berzelius’s objections, repeated his experiments, still asserts their accuracy. The author of the present paper investigated the subject with the greatest care, employing materials in a state of perfect purity, and obtained results which coincided with those of Berzelius. He details the pre­cautions he took for ensuring the conditions of perfect purity in the substances with which his experiments were made, and to the neglect of which he traces some of the errors which he imputes to Dr. Thomson’s analysis. But there exists also a more radical cause of error in the method employed by that chemist; for Dr. Turner finds that when solutions of muriate of baryta and of sulphate of potash are mixed together, a small portion of the latter salt adheres tenaci­ously to the sulphate of baryta, which is precipitated, and escapes decomposition. By employing different processes the author avoids this source of fallacy; first, from the chloride of barium, previously dissolved in water, he throws down sulphate of baryta by adding sulphuric acid; and, secondly, he effects a precipitation from a simi­lar solution of the chloride, by nitrate of silver, and infers the quantity of chloride from that of the fused horn-silver obtained, having pre­ viously determined, by a separate series of experiments, the exact composition of horn-silver. The conclusion he draws from his re­searches is, that 100 parts of chloride of barium correspond to 137·63 parts of the chloride of silver, which latter substance contains 34·016 parts of chlorine, and therefore leaves for the proportion of barium 65·984 parts. The real equivalent of barium, however, will depend upon that of chlorine, which is itself not yet satisfactorily de­termined.