Preparation and standardization of 1 M Sodium Hydroxide BP Volumetric Solution

Preparation and standardization of 1 M Sodium Hydroxide BP Volumetric Solution

1.  PREPARATION:

Dissolve 42 g of Sodium hydroxide in carbon dioxide free water and dilute to 1000 mL with same solvent.

2. STANDARDISATION:

Dissolve 1.50 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 1 M Sodium hydroxide is equivalent to 204.2 mg of C8H5KO4.

Calculation:

Molarity (M) = [1 x Weight of Potassium hydrogen phthalate (in g)]/ [0.2042 x Titration reading (in mL)]                               

Limit: 1 M ± 5 % (0.9500 M –1.0500 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.

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