pH of pure DPG is around 4-5, DIW around 5.50, but when both are mixed together in 9 part DIW with 1 part vol DPG the pH drops to 3.49. What could be the explanation for this observed change in pH?
Please define the abbreviation before use it. Besides, I guess that there is something concerning the modification of the dielectric constant of the solvent X due to the addition of Y.