Official Methods of Analysis. Association of Official Analytical Chemists . This method is applicable for the preparation and standardization of standard sodium hydroxide solution. Sodium hydroxide solution, to 1 part reagent grade NaOH add 1 part distilled, carbon dioxide-free water by weight. Acid potassium phthalate, NIST SRM for Acidimetry 84, dry for 2 hr at 120oC and cool in desiccator.
Alkalis can burn skin, eyes and respiratory tract severely.
Use effective fume removal device to protect against alkali dusts or vapors. Always add sodium hydroxide pellets to water, not vice versa. Add 50 mL CO2-free water, stopper flask and swirl until sample dissolves. Titrate to pH 8.6 with solution being standardized, taking precautions to exclude CO2 and using as indicator either glass-electrode or phenolphthalein. If using indicator, add 3 drops phenolphthalein to a flask containing 50 mL of pH 8.6 buffer and stopper.