define reagents for estimation of calcium using

Question

Define Reagents for Estimation of Calcium Using EDTA Titrimetric Method?

1. Buffer solution: Dissolve 16.9 g NH₄CI in 143 ml NH₄OH. To this add 50 ml of solution containing 1.17g Na₂EDTA. 2H₂O and 0.644 g MgCI₂ . 6 H₂O and dilute to 250 ml with distilled water.

2. Indicator: This contains a mixture of 0.5 g Eriochrome black T and 100 g NaCI. It is used in a dry form.

3. EDTA solution (0.01 M): Weigh 3.723 g Na₂EDTA. 2 H₂O and dilute to one liter with distilled water.

4. Standard calcium solution: Calcium carbonate solution containing 1 mg/ml of calcium carbonate.

5. Distilled water