Preparation and standardisation of 0.1 M Sodium Hydroxide BP volumetric solution
Dilute 100 mL of 1 M Sodium Hydroxide to 1000 mL with carbon dioxide free water.
Dissolve 0.150 g of Potassium hydrogen phthalate in 50 mL of water. Titrate with the Sodium hydroxide solution, determining the end point potentiometrically or using 0.1 mL of Phenolphthalein solution as indicator.
1 mL of 0.1 M Sodium hydroxide is equivalent to 20.42 mg of C8H5KO4.
Molarity (M) = [0.1 x Weight of Potassium hydrogen phthalate (in g)]/ [0.02042 x Titration reading (in mL)]
Limit: 0.1 M ± 5 % (0.0950 M – 0.1050 M)
3. PREPARATION OF INDICATORS / REAGENTS:
a. Phenolphthalein solution :
Dissolve 0.1 g of Phenolphthalein in 80 mL of Ethanol (96 %) and dilute to 100 mL with water.
4. STORAGE CONDITION:
Store in glass stoppered bottles.