Boil mL of N sulfuric acid with about 1 g of Zinc Undecylenate, accurately weighed, for 10 minutes, or until the undecylenic acid layer is clear, adding water, as necessary, to maintain the original volume. Cool, and transfer the mixture, with the aid of water, to a 500-mL separator. Dilute with water to about 250 mL, and extract with two 100-mL portions of solvent hexane. Wash the combined extracts with water until the last washing is neutral to litmus, add the washings to the original water layer, and evaporate on a steam bath to about 100 mL. Cool, add 3 drops of methyl orange, and titrate the excess sulfuric acid with N sodium hydroxide. Perform a blank determination. Each mL of N sulfuric acid is equivalent to mg of C22H38O4Zn.