I am trying to make 1M triethylammonium acetate with triethylamine solution and glacial acetic acid solution. I am mixing them in the recommended volumes to yield a 1M solution (6.97mL triethylamine and 2.86mL glacial acetic acid; 1 mole each)

The pH of the resulting solution should be basic because the recommendations everywhere suggest to adjust the pH "to" 7.0 with diluted acetic acid.

However, when I add the said volumes of the two chemicals to deionized water, I always reach a pH of 4-5. Which would mean that there is more of the acid in the solution than the base.

This is very perplexing because mathematically, by adding the recommended volumes, I am adding 1 mole of each compound.

If I stop adding glacial acetic acid when the pH reaches 7.0, I could assume that the solution is neutral at this point. But at this point, I am adding only 0.7 moles of the acid (I know this because I track the volume of acetic acid added and back-calculate the number of moles contained in this volume). Which makes the solution not equimolar.

Am I missing some very basic concept of chemistry? Or is something really wrong?

Can someone help?

P.S. The pH of the water I use is at 8.5-9

Thanks!