Section 21.96 - Ammonia, aqueous(a)Alkalinity. Strongly alkaline to litmus.(b)Ammonia content. 27 to 30 percent by weight. Accurately weigh a glass-stoppered flask containing 25 ml of water, add about 2 ml of the sample, stopper, and weigh again. Add methyl red indicator, and titrate with 1 N sulfuric acid. Each ml of 1 N sulfuric acid is equivalent to 17.03 mg of NH3(c)Color. Colorless liquid.(d)Non-volatile residue. 2 mg maximum. Dilute a portion of the sample with 11/2 times its volume of distilled water. Evaporate 10 ml of this product to dryness in a tared platinum or porcelain dish. Dry residue at 105 °C. for 1 hour, cool and weigh.(e)Odor. Characteristic (exceedingly pungent).(f)Specific gravity at 20 °/4 °C. 0.8920 to 0.9010.T.D. ATF-133, 48 FR 24673, 6/2/1983. Redesignated by T.D. ATF-442, 66 FR 12854, 3/1/2001