Why does the acetyl group drop the pH? I have a molecule that is 8% of the R groups are replaced with Acetyl groups.  When I dissolve it in water it drops the pH.  I am trying to understand why.
Because the electrons in the double bond C=O help to stabilize the CH3 group after it has released an H+ (it is similar in this way to what happens with carboxylic acids), the Acetyl groups are acid. Hence the pH drop.