On the application of the conversion of chlorates and nitrates into chlorides, and of chlorides into nitrates, to the determination of several equivalent numbers / by Frederick Penny.

  • Penny, Frederick, 1816-1869.
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: On the application of the conversion of chlorates and nitrates into chlorides, and of chlorides into nitrates, to the determination of several equivalent numbers / by Frederick Penny. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    4/24 (page 4)
    ride of potassium will be 76 and 74-6. Whence, according to the former, every 100 parts of nitrate should yield 74-51 of chloride: the latter gives the ratio of 100 to 73-61 3. But these results differ considerably from my experiments. In the one case we have a difference of -78, and in the other -12. Whence therefore could they arise? Either the process must be defective, or the equivalent numbers, so generally considered as correct, must be erroneous. 3. To determine whether the process was inaccurate, I tried if chloride of potas sium could be converted into nitrate of potassa by nitric acid. A single experiment upon some pure chloride decided in the affirmative; and the mean result of three ex- periments gave the ratio of 100 of nitrate to 73*727 of chloride. The correctness therefore, of the experiments upon the nitrate was satisfactorily confirmed. More- over in another experiment I converted a known weight of nitrate into chloride by hydrochloric acid, and then reconverted the resulting chloride into nitrate by nitric acid. The quantity of nitrate obtained was very nearly the same as that originally employed ; there was not a hundredth of a grain difference. The error was thus traced to the equivalent numbers, but whether it existed in one, or more, of the ele- mentary bodies constituting the above compounds, remained still unknown. The subject cannot be decided by the mere conversion of a nitrate into a chloride, or a chloride into a nitrate. Additional data are required. In order therefore to exa- mine the question more scrupulously, the following experiments were undertaken • and as the results have proved consistent and satisfactory, I have presumed to submit them to the Royal Society. 4. In the present communication I propose to examine the equivalent numbers of oxygen, chlorine, nitrogen, potassium, sodium, and silver; and the following are the sue- cessive steps by which this examination has been conducted. ; 5 In tlle first place the equivalent of chloride of potassium will be determined, by ecomposmg the chlorate of potassa into oxygen, and chloride of potassium. From the ratio which these results bear to each other, the number for chloride of potassium, as compared with oxygen, may be easily deduced. The same results will also give the number for chlorate of potassa. Secondly, The equivalent of nitrate of potassa is ascertained. This is effected by converting the chlorate of potassa and the chloride of potassium into nitrate: and as we have already established the equivalents of chlorate and chloride, we can easily calculate the number for nitrate from these two methods of analysis. Moreover, rom the equivalents of chlorate and nitrate of potassa, we can also learn the differ- ence between the equivalents of chlorine and nitrogen, as the two salts agree ex- actly m composition, and only differ by nitrogen in the one being substituted for c ilorine in the other. To confirm the experiments upon the conversion of chloride o potassium into nitiate, I have detailed some upon the decomposition of nitrate into chloride. Tiie process, hereafter described, by which these experiments were performed, was