Preparation and standardization of 0.5 N Hydrochloric acid USP Volumetric Solution
1. PREPARATION :
To a 1000 ml volumetric flask containing 40 ml of water slowly add 43 ml of Hydrochloric acid. Cool, and add water to volume.
2. STANDARDISATION :
Accurately weigh about 2.5 g of Tromethamine dried according to the label instructions. Dissolve in 50 ml of water, and add 2 drops of Bromocresol green TS. Titrate with 0.5 N Hydrochloric acid to a pale yellow endpoint.
Each 60.57 mg of Tromethamine is equivalent to 1 ml of 0.5 N Hydrochloric acid.
Normality (N) = [Weight of Tromethamine (in g)]/[ 0.12114 x Titration Reading (in ml)]
Limit : 0.5 N ± 5 % (0.4750 N – 0.5250 N)
3. PREPARATION OF INDICATORS / REAGENTS :
a. Bromocresol green TS:
Dissolve 50 mg of Bromocresol green in 100 ml of Alcohol and filter if necessary.
4. STORAGE CONDITION :
Store in glass-stoppered bottles.