Name: How to Preparare and Standardization of 0.1 M Disodium Edetate (EDTA
|3.||Eriochrome black – T|
|4.||Ammonia – Ammonium Chloride Buffer pH10 (Mix 5.4 grams of NH4Cl + 35 milliliters of 10M NH3 solution & dilute to 100 milliliters with water.)|
How to Prepare :
Dissolve 37.2 grams of disodium edetate in enough water to make 1000 milliliters.
How to Standardization:
- Take about 200 milligrams of dry CaCO3 (previously dried at 110ºC for two hours),
- Mix it with a little hydrochloric acid.
- Add 50 milliliters of clean water and 10 to 15 milliliters of Ammonia – Ammonium Hydroxide Buffer.
- Then, use 0.1M EDTA to test it.
- The color will change from purple to dark bluish.
- Each milliliter of 0.1 M EDTA is equivalent to 0.010009 grams of CaCO3.
Calculating the Result:
Weight of CaCO3 (grams) X 0.1 x Amount of CaCO3
Burette Reading x 0.010009 X 100
B.R.: The reading on the Burette in milliliters.
Sources: Indian Pharmacopoeia / United States Pharmacopoeia