关于titration of EDTA

891108

I. Colour changes of Eriochrome Black T upon complexation with magnesium ions
in HCl solution, NaOH solution and NH3/NH4Cl buffer at pH 10 (Work in pairs)
1. Label three test tubes and add 5 mL of the following solutions separately into
each test tube:
Test tube A: 1 M HCl
Test tube B: 1 M NaOH
Test tube C: NH3/NH4Cl buffer solution at pH 10
2. Add 10 mL of distilled water and 3 drops of Eriochrome Black T into each test
tube. Observe the colour of the solution in each test tube.
3. Add 1 mL of the magnesium nitrate solution into each test tube from Step 2.
Observe the colour change of the solution in each test tube.
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请问equation应该如何写？
HCL+ EDTA+ H20 >>>> formed什么complex呢？
头痛死了