This International Standard specifies a method for determining the total free alkali content of commercial soaps, excluding compositions.1) This method is not applicable when the soap contains additives (alkali silicates, etc. .) capable of being decomposed by sulfuric acid under the conditions of the test. This method is also not applicable to colored soaps if the color interferes with the assessment of the change in phenolphthalein.
NBN T 63-106-1980 history
1980NBN T 63-106-1980 Analysis of soaps - Determination of total free alkaLi