Preparation and standardization of 0.025 M Sulfuric acid EP Volumetric Solution
1. PREPARATION :
Dilute 50 mL of 0.5 M Sulfuric acid to 1000 mL with water.
2. STANDARDISATION :
Dissolve 0.050 g of Trometamol in 50 mL of water. Titrate with the Sulfuric acid solution, determining the end point using 0.1 mL of Methyl orange solution as indicator until the solution turns reddish-yellow.
1 mL of 0.025 M Sulfuric acid is equivalent to 6.055 mg of C4H11NO3.
Molarity = [0.025 x wt. of substance ( g. ) ]/[ 0.006055 x Titration Reading]
Limit: 0.025 M ± 5 % (0.0238 M – 0.0263 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.