73
FEBRUARY, 1948
APPARATUS FOR THE SEMIMICRO TEST FOR A CARBONATE FRED H.HEATH University of Florida, Gainesville, Florida
BY
THE ordinary test for a carbonate, the unknown is treated with hydrochloric acid, warmed, and the evolved carbon dioxide is passed into a solution of calcium hydroxide, where it causes precipitation of calcium carbonate. Under the common working conditions of the laboratory there is distinct risk of a false test from the presence of carbon dioxide either from the exhaled air of the operator or from a near-by gas flame. The apparatus here outlined is designed to avoid such errors as well as to work convenientlywithsmallamounts of material. The glass apparatus rests on the top of a test tube, as indicated in the illustration. The small opening in the glass apparatus permits introducing the calcium hydroxide by use of a medicine dropper and it prevents false tests by carbon dioxide entering the apparatus from outside sources. The large exposed surface of the solution of calcium hydroxide results in rapid absorption of the carbon dioxide, and the test is quickly made. The apparatus is cheap, simple, and easily cleaned. This apparatus can be used for other tests, such as the chromyl chloride test for a chloride in the presence of bromide or iodide.
