Estimation of Calcium Gluconate by Complexometric Titration

Introduction of Estimation of Calcium Gluconate by Complexometric Titration:

• Estimation of Calcium Gluconate by Complexometric Titration in pharmaceutical analysis, calcium gluconate (Ca(C₆H₁₁O₇)₂) is estimated using complexometric titration with EDTA as the titrant.
• The titration is based on the formation of a stable complex between EDTA and calcium ions (Ca²⁺).

Apparatus and Reagents:

1. Burette
2. Erlenmeyer flask
3. pH meter or pH indicator
4. Calcium gluconate solution (sample)
5. Standard EDTA solution (0.01 M)
6. Buffer solution (pH ~10)
7. Eriochrome Black T indicator (optional)

Procedure of Estimation of Calcium Gluconate by Complexometric Titration:

1. Preparation of Sample:

   • Weigh a sample of calcium gluconate (Ca(C₆H₁₁O₇)₂).
   • Dissolve it in distilled water and transfer to an Erlenmeyer flask.

2. Prepare EDTA Solution:

   • Use a standard EDTA solution, typically 0.01 M.

3. Buffering:

   • Add a buffer solution to the calcium gluconate sample to maintain a pH of ~10.

4. Add Indicator (optional):

   • If using Eriochrome Black T, add a few drops. The solution will turn pink due to the presence of calcium ions.

5. Titration:

   • Titrate the calcium gluconate solution with EDTA solution from the burette.
   • As EDTA forms a complex with Ca²⁺, the solution’s color will persist (pink if using Eriochrome Black T) until all calcium ions are complexed.

6. Endpoint Detection:

   • The endpoint is detected when the color changes, typically from pink to blue (if using Eriochrome Black T) or a noticeable change in solution color.
   • Note the volume of EDTA required to reach the endpoint.

Calculations:

• Amount of Ca(C₆H₁₁O₇)₂ (in grams):

• Amount of Ca(C₆H₁₁O₇)₂ = (Volume of EDTA × Molarity of EDTA × Molar mass of Ca(C₆H₁₁O₇)₂) ÷ 2

• The factor of 2 accounts for the stoichiometry, as each Ca²⁺ ion reacts with one mole of EDTA.

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