EDTA Disodium Stock pH Adjustment

Estimate how much strong base to add to bring an ethylenediaminetetraacetate disodium solution to the desired pH. This tool models the third and fourth dissociation steps and provides guidance on practical limits for precise preparation.

Inputs

How to use

  1. Enter the stock strength of disodium EDTA and the volume you are preparing.
  2. Measure the starting pH of your mixture after dissolving as much as possible.
  3. Choose your target (commonly 8.0–8.5 for many protocols).
  4. Provide the concentration of your NaOH titrant.
  5. Press Calculate to get an estimated volume of base to add.

FAQs

EDTA dissolves and complexes better when deprotonated. Around pH 8, most EDTA is in the HY³⁻/Y⁴⁻ forms, improving solubility and chelation in many applications.
Strong base is typical. Alternatives like potassium hydroxide also work; adjust the concentration accordingly. Avoid weak bases that make pH control sluggish.
Real systems vary with ionic strength, temperature, impurities, and instrument calibration. Use the result as a starting point, then fine‑tune by titrating to the exact setpoint.
Yes. Many protocols wet the powder with water and add small portions of solid base to dissolve before making to volume. Add cautiously and monitor pH.
Consider preparing a more concentrated EDTA stock or using a stronger titrant so the added volume stays modest. Excess addition can change final composition significantly.
Defaults are pKₐ₃≈6.16 and pKₐ₄≈10.26. You can override them if your reference or temperature suggests slightly different constants.
Temperature slightly shifts equilibria. For routine lab work at room temperature, this model is adequate. For precise analytical work, measure pH at the working temperature.

This tool provides an engineering estimate for planning and education. Always verify by measuring pH during preparation.

Load jQuery Load JS Bundle

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.