Standards And Tests for Reagent Chemicals

rating in the presence of ammonium salts, and is not suitable for use with acetic acid and most other organic acids, though oxalic acid reacts sharply with it. It is used largely in gastric analysis and water analysis. Rosolic acid should be stored in a cool place as otherwise it is liable to soften and become coherent. Method of Testing Add 2 or 3 drops of rosolic acid test solution to 100 mils of water and add 0.05 mil of tenth-normal solution of sodium hydroxide. A red color should be produced in the liquid which should be changed to yellow by the subsequent addition of 0.05 mil of tenth-normal hydrochloric acid solution. ACID SALICYLIC HC7H.O2 Mol. Wt. 138.05 Salicylic acid usually occurs as fine, white, odorless, needle- like crystals or a crystalline powder. It is only slightly soluble in cold water (about 500 parts) but is soluble in about 2 parts of alcohol or ether and in about 30 parts of chloroform. It melts at about 157 C. (theory 159.05 C.). The reagent is used principally for the detection of nitrites, acetone, titanium, formaldehyde, methyl alcohol and lactic acid and in nitrogen determinations by the Kjel- dahl or Gunning method to include nitrate-nitrogen. Salicylic acid is easily discolored by even traces of iron, such as may occur in dust. It should therefore be kept in well-stoppered containers. Maximum Limits of Impurities Non-volatile Matter 0.1000% Organic Impurities 0.0000% Chlorides (Cl) 0.0020% Methods of Tes...