Preparation and standardization of 0.1 M Hydrochloric acid EP Volumetric Solution
1. PREPARATION:
Dilute 100 mL of 1 M Hydrochloric acid to 1000 mL with carbon dioxide free water.
2. STANDARDISATION:
Dissolve 0.095 g of Trometamol in 20 mL of water. Titrate with the hydrochloric acid solution, determining the end point potentiometrically or using 0.1 mL of Methyl orange solution as indicator until a yellowish-red colour is obtained.
1 mL of 0.1 M Hydrochloric acid is equivalent to 0.01211 g of C4H11NO3.
Calculation:
Molarity (M) = [0.1 x Weight of Trometamol (in g)]/[ Titration reading (in mL) x 0.01211]
Limit: 0.1 M ± 5 % (0.0950 M – 0.1050 M)
3. PREPARATION OF INDICATORS / REAGENTS:
a. Methyl orange solution:
Dissolve 0.1 g of Methyl orange in 80 mL of water and dilute to 100 mL with Ethanol (96 %).
Test for sensitivity: A mixture of 0.1 mL of the Methyl orange solution and 100 mL of carbon dioxide free water is yellow. Not more than 0.1 mL of 1 M Hydrochloric acid is required to change the colour to red.
Colour change: pH 3.0 (red) to pH 4.4 (yellow).
4. STORAGE CONDITION:
Store in glass stoppered bottle.