Packaging and storage—
Preserve in tight, light-resistant containers.
Identification—
B:
Place 3 mL of it and 3 mL of freshly distilled aniline in a tall test tube, and heat for 10 minutes at a rate such that the ring of condensate remains just below the mouth of the tube. Cool, add 10 mL of alcohol and 10 mL of ether, and transfer to a separator. Wash the ether solution with four 20-mL portions of water, and discard the water washings. Heat on a steam bath until the odor of ether no longer is perceptible, then add a few mg of activated carbon, mix, and filter. Evaporate the filtrate nearly to dryness, and recrystallize the residue from 70 percent alcohol: the anilide so obtained melts between 66
and 67.5
.
Water-soluble acids—
Shake 5 mL with 5 mL of water, and filter the water layer through a filter paper previously moistened with water. Add 1 drop of
methyl orange TS, and titrate with 0.01 N sodium hydroxide VS: not more than 1.0 mL of 0.010 N sodium hydroxide is required to match the color produced by 1 drop of
methyl orange TS in 5 mL of water.
Heavy metals, Method II 
231
:
0.001%.
Assay—
Dissolve about 750 mg of Undecylenic Acid, accurately weighed, in 50 mL of alcohol, add 3 drops of phenolphthalein TS, and titrate with 0.1 N sodium hydroxide VS to the first pink color that persists for not less than 30 seconds. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sodium hydroxide is equivalent to 18.43 mg of C11H20O2.
;)
