5 N Sodium hydroxide: Dissolve 200 g NaOH in distilled water, cool, and dilute to 1 L. 0.1 mg F ­ /mL stock solution: Dissolve 0.2210 g NaF in distilled water and dilute to 1 L in volumetric flask. Transfer to polyethylene bottle for storage.
When sodium hydroxide is dissolved in water, it dissociates hydroxide ion and sodium ion. NaOH (aq) ⇨ Na + + OH − Similarly, when potassium hydroxide is dissolved in water, it dissociates hydroxide ion and potassium ion. KOH (aq) ⇨ K + + OH − Thus, base shows its basic character because of dissociation of hydroxide ion.