Manual of qualitative analysis / by Robert Galloway.

  • Galloway, Robert.
Date:
1861
Catalogue details

Licence: Public Domain Mark

Credit: Manual of qualitative analysis / by Robert Galloway. Source: Wellcome Collection.

    176/272 (page 158)
    381. Hyprocyanic Acip.— This acid can be distin- guished from all other acids by the tests described in para- graphs 452 and 454; if, however, protoxide of mercury has been discovered in testing for the bases, the process de- scribed in paragraph 455 must be employed. 382. Arsmntous Actp, ARsENIc AcIp, CuHromic Acip. —As these acids are discovered in testing for the bases, no experiments require to be made for their detection when testing for the acids. 383. SutpHuRic Acrp.—The presence or absence of this acid is ascertained on testing a part of the solution with the general reagent, chloride of barium ; no further test is needed to prove its absence or presence. 384. Boracrc Actp.—This acid can be detected, in most cases, by the method described in paragraph 416; but the most certain test is the one described in paragraph 417. 385. PaospHortc Acip.— When the phosphates are solu- ble in ammoniacal solutions (and the student can decide this when he knows what bases are present), this acid can be detected by the method described in paragraph 422, but the most certain tests are 425 and 426, especially the last. The student must, however, remember that arsenic acid gives precipitates with these reagents, similar to those given by phosphoric acid. “When arsenic acid is present, it must, on this account, be removed from the solution by sulphide of hydrogen, or be reduced to the state of arsenious acid, before testing for phosphoric acid. 386. Oxatic Acrp.—This acid is detected by the method described at 483 ; but very minute quantities of it are more securely detected by boiling the substance with a solution of carbonate of soda, for some time; subsequently filtering, and the filtrate acidifying with acetic acid, and then adding to it a solution of sulphate of lime (432).