Laboratory experiments in organic chemistry designed especially for use with Stoddard's; Introduction to organic chemistry

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ... ORGANIC CHEMISTRY ANALYSIS OF ORGANIC SUBSTANCES Detection of Carbon.--Test the following substances for carbon by heating a small amount of each, the first two on a porcelain crucible cover, the third in a test tube: tartaric acid; benzoic acid; alcohol. (a)The Substance Blackens or Chars.--Carbon is probably present. (b)It Bums.--Is the flame smoky? If not, hold a dry test tube inverted just above the flame, and then shake lime water in it. What does this prove? c)It Sublimes.--Mix some of the substance with fine copper oxide, put into a hard glass test tube and cover with a layer of copper oxide. Arrange to lead the gas formed into lime water, using a one-hole rubber stopper. Heat the copper oxide layer first and then the substance itself with a low flame. How can you show in these tests that hydrogen also is present? Detection of Nitrogen.--1. Notice the odor when a piece of horn or some hair is burned. 2. Heat a bright piece of sodium the size of a small pea in an ignition tube with a little of the substance to be tested. (Use aniline chloride.) Heat gently until the sodium is melted and the substance begins to char, then increase the temperature until the tube is bright red and continue heating until there is no further change in the substance. Cool a little, but while still hot break the tube by dipping the end into 5 cc. of water in a small porcelain dish, being very careful that the unchanged sodium does no harm. Break up the lumps, and warm the contents of the dish for a few moments; filter and divide the filtrate into two portions. (If the filtrate is colored it indicates insufficient heating and the test should be repeated.) To one portion add a few drops of ferrous sulphate and a drop of ferric chloride, and then acidify with hydrochloric acid...