Preparation and standardization of 0.5 M Sodium Hydroxide BP Volumetric Solution

1.  PREPARATION:

Dissolve 21 g of Sodium hydroxide in sufficient carbon dioxide free water to produce 1000 mL.

2. STANDARDISATION:

Titrate 20 mL of the solution with 0.5 M Hydrochloric acid VS using the indicator prescribed in the assay in which the solution to be used.

Each mL of 0.5  M Hydrochloric acid VS is equivalent to 0.02 g of NaOH.

Calculation:

Molarity (M) = [Titration reading (in mL) x Exact Molarity of 0.5 M HCl]/[20]                 

Limit: 0.5 M ± 5 % (0.4750 M – 0.5250 M)

3. PREPARATION OF INDICATORS / REAGENTS :

a. 0.5 M Hydrochloric acid :

Preparation and standardization as per respective procedure.

4. STORAGE CONDITION :

Store in glass-stoppered bottles.