Soap Solution.—Scrape 10 gms. of castile soap into fine shavings and dissolve in a liter of alcohol, dilute with 1/3 water. Filter if not clear and keep in a tightly stoppered bottle.
1. Why is more soap required to form a lather with hard water than with soft water? 2. What is meant by "lime soap"? Describe its appearance. 3. How may hard waters be softened for household purposes?
Experiment No. 44
Solvent Action of Water on Lead
Put 1 gm. of clean bright lead shavings into a test tube containing 10 cc. of distilled water. After 24 hours decant the clear liquid into a second test tube, acidify slightly with HCL, and add a little hydrogen sulphid water. A black or brownish coloration indicates lead in solution.
(Adapted from Caldwell and Breneman, "Introductory Chemical Practice.")
Under what conditions may lead pipes be objectionable?
Experiment No. 45
Suspended Matter in Water
Place a drop of water on the microscopical slide, cover with cover glass, and examine with the microscope. Note the occurrence and appearance of any suspended matter in the water.