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Standar Nasional Indonesia

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25 June 2011

Preparation and Standardization of Potassium Hydroxide, Methanolic, 0.1 N

Dissolve 6.8 g of potassium hydroxide in a minimum amount of water (about 5 mL), dilute to 1 L with methanol, and mix thoroughly. Allow to stand in a container protected from carbon dioxide for 24 h. Carefully decant the clear solution, leaving any residue behind, into a suitable container, mix well, and store protected from carbon dioxide. Standardize as follows: Weigh accurately about 0.85 g of potassium hydrogen phthalate, Acidimetric Standard, previously lightly crushed and dried for 2 h at 120C. Dissolve in 100 mL of carbon dioxide-free water, add 0.15 mL of phenolphthalein indicator solution, and titrate with the methanolic potassium hydroxide solution to a permanent faint pink color.