EDTA titration to determine Calcium. Standardization solution. Approximately 0.0

ID: 484943 • Letter: E

Question

EDTA titration to determine Calcium.

Standardization solution.

Approximately 0.01 M solution of EDTA was prepared.

Approximately 0.008M solution of primary grade CaCO3 (due to insolubility we added HCl and made calcium chloride solution)

Standardization results were (volume of EDTA added until endpoint):

38.71 mL, 38.53mL, 38.52 mL

To detemine the CaO in an unknown sample, we made the solution with an unknown sample (assumed 40-55% CaO by mass) which we added 0.4421g of unknown.

Volume added to reach the endpoint for unknown solutions were:

29.50 mL, 28.36mL, 29.63 mL.

How do you make the titration curve?

How do you determine % CaO in unkown?

Titration curve is prepared by ploting pCa in Y axis and volume of EDTA in X axis.

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Steps :

1. Calculate the exact molarity of EDTA for standardization titration.

2. Calculate amount of Ca by using the formula M1V1 = m2 V2

M1 = molarity of EDTA, V1 = volume of EDTA, M2= ?, V2 = volume of solution containing unknown

3. Calculate mass of CaO

Molarity = moles/L

mass = moles * molar mass of CaO

4. % = mass of CaO/mass of unknown * 100

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