I have weighed 27.91 grams of EDTA (disodium dihydrate M.WT 372.2) to be prepared in a final volume 25 ml to have a 3M solution. I placed them in a beaker placed on a magnet stirrer and added 15 ml of distilled water and placed the electrode of the pH meter in the beaker and started adding NAOH pellets until the pH meter has read 8. The NAOH pellets were dissolving but the EDTA was no dissolving. What shall I do?
This information says that the solubility of EDTA in water is 100 g/L https://www.applichem.com/en/shop/product-detail/as/edta-dinatriumsalz-dihydrat-ibiochemicai/. You are trying to disslove over a 1100 g/L. Adjusting the pH might help with this a bit, but maybe not that much. Maybe increasing the pH to 8.5 could help? As I don't know what you are trying to make this for, it is difficult to make suggestions that might be helpful.
If keep adjusting the pH, the EDTA should eventually dissolve. This is a really high concentration of EDTA you are trying to make, so a lot of NaOH is probably needed to get it to dissolve. IF you could make a lower concentration EDTA solution, this would be more soluble.
This information says that the solubility of EDTA in water is 100 g/L https://www.applichem.com/en/shop/product-detail/as/edta-dinatriumsalz-dihydrat-ibiochemicai/. You are trying to disslove over a 1100 g/L. Adjusting the pH might help with this a bit, but maybe not that much. Maybe increasing the pH to 8.5 could help? As I don't know what you are trying to make this for, it is difficult to make suggestions that might be helpful.
If the (maximum) solubility of EDTA in water is 100g/L (https://www.applichem.com/en/shop/product-detail/as/edta-dinatriumsalz-dihydrat-ibiochemicai/) I would not expect any MAGIC will happen with NaOH or any other agents. May be you can find any other alternates for EDTA?
The maximum solubility is certainly above 100g/L as many standard lab protocols use a 0.5M stock solution (186g/L). It does however require a lot of NaOH and time to get this. I very much doubt that a 3M solution is physically possible, so you will have to redesign your experiment.
Not sure neither that 3M EDTA is possible to get. Probably, light warming in water bath with increased pH up to 8,5 and continuously mixing may help a bit.
Hi Ananda, the solubility of most materials is pH dependent, so adding NaOH to increase the pH facilitates the dissolution of acidic EDTA. As Matthew says, 0.5M EDTA is fine to make, as long as you adjust the pH appropriately. It's not magic, it's chemistry.
yes as others I do agree for making 0.5 molar (we also make it in our lab) but not 3 or 30 molar with NaOH or any other magic salts. please let me know Johanna if you find one!
You could try the tetrasodium salt of EDTA. The maximum solubility of Na4EDTA is about 110g/100 ml (http://mistralni.co.uk/products/edta-na4-ethylenediaminetetraacetic-acid-tetra-sod) at 20°C, so you could theoretically get a solution that is 2.89 M. Of course the pH of the solution would be higher than 8. This is really not different from continuing to add NaOH to your EDTA until it goes into solution, but you will have to stay below 2.89 M and allow the pH to rise higher than 8. As Johanna so eloquently stated: "It's not magic, it's chemistry."
Hi, today I had exactly the same issue in lab where I tried dissolving in water, turns out there is actually an EDTA disodium salt dihydrate which dissolves immediately and without the addition on any base. Make sure you buy the right chemical
- Badges
- Science method