Preparation and standardization of 1 M Hydrochloric acid EP Volumetric Solution
1. PREPARATION :
Dilute 103.0 g of Hydrochloric acid to 1000.0 mL with water.
2. STANDARDISATION :
Dissolve 0.950 g of Trometamol in 50 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 1 M Hydrochloric acid is equivalent to 0.1211 g of C4H11NO3.
Molarity (M) = [1 x Weight of Trometamol (in g)]/[Titration reading (in mL) x 0.1211]
Limit: 1 M ± 5 % (0.9500 M – 1.0500 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.