Whoops! There was a problem with CHEM 1100 5.80a. I was reminded by a student that after 10 mL of base have been added, there are now appreciable amounts of both the acid, HF, and the conjugate base, F^1-. I’ve fixed the pH calculation for that part.

I corrected 9.16a for CHEM 1050.

I checked problem 15.80 for CHEM 1100 and the posted solutions are correct. Part c establishes that it takes 50 mL of the base to get to the equivalence point. Part d asks about 80 mL which is 30 mL past the equivalence point.

I fixed a problem for CHEM 1050, 5.26 and CHEM 1100, 14.71 and 14.72.