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.

    72/272 (page 54)
    128. The precipitate produced by the general reagent, car- bonate of ammonia, must be dissolved in acetic acid, and the solution divided into two parts, which we shall call A and B. 129. Before we describe the way for separating the mem- bers of this division of the group, we shall propose six ques- tions, which the student ought to solve by the aid of the table before he attempts the detection of baryta, strontia, and lime. 1st, Why are the precipitated carbonates directed to be dissolved in acetic acid; why not dissolve them in hydrochloric acid or nitric acid? 2nd, By what single re- agent can we discover, in one operation, the absence of baryta and strontiaP? 38rd, How can lime be detected in the absence of the other two members? 4th, How can strontia be detected in the absence of baryta? 5th, Can lime be detected when strontia is present? 6th, Can strontia and lime be detected when baryta is present. 130. SULPHATE OF LIME precipitates baryta immediately, strontia after the lapse of some time, and lime not at all (see D1,E1, and F 1). One of three cases will, therefore, occur on the addition of sulphate of lime to the A portion ; either there will be no precipitate, or there will be one after the lapse of some time, or there will be an immediate one. If there is no precipitate, examine according to par. 131; if there is one after the lapse of some time, examine according to par. 132; if there is one immediately, examine according to par. 133. 131. If, in the A portion, a solution of sulphate of lime causes no precipitate, even after the lapse of some time, BARYTA and STRONTIA are absent ; LIME must therefore be present*—as one of the members of a group must, at least, * If the previous group or groups have been fully precipitated before adding the carbonate of ammonia, or else they might—that is, the por- tion not precipitated—cause a precipitate with carbonate of ammonia.