I have not the faintest clue about zinc or your overall question, but this part:
saliva pH is 5; over 100 times more acidic than pH of cellular environment which is 7.4
7.4 is basic, right? “100 times more acidic than [something on the other side of neutral]” seems like a weird thing to say?
pH is basically the (negative) exponent in the concentration of H+; a concentration of 10^-2 gives a pH of 2, a concentration of 10^-7 gives a pH of 7. So moving from 5 to 7 on the pH scale is a factor of 100 in the concentration of H+. That’s why they say it’s “100 times more acidic”. (Also, the neutral point in the pH scale is neutral because that’s the concentration at which the positive H+ ions are balanced by negative...usually OH-...ions.)
For the most part, and to my limited memory of chem...yes.
Umm. Hmm. *goes back and reads the relevant parts of your post* I don’t know any of this off the top of my head. Let’s see… Wiki says zinc acetate is a salt of zinc and acetic acid. Ok, so zinc acetate is already zinc ions and acetate ions. (CH3CO2-). Two of those ions for each Zn, so each Zn ion is Zn+2. You stick the Zn(CH3CO2)2 into the pH 5 saliva solution, which has a lot of extra H+ sticking around. The H+s in the pH 5 solution are already outnumbering any loose negative ions...that’s what it means to be pH5. So when you stick the salt in it, the H+s grab the negative acetate ions and tear the salt structure apart. The Zn becomes free-floating ions because there aren’t enough negative ions around to bind with them.
If you drop the zinc acetate in a neutral solution, it might still dissolve into ions; sometimes with water, what happens is basically everything just pulls at everything else, and things stay in constant flux instead of settling into neutral compounds. [This is my understanding of what happens with NaCl, for example: you don’t get NaOH and HCl so much as you get lots of Na+ and Cl- floating around in H2O with the H+ and OH-, constantly forming and unforming all the possible combinations in insignificant amounts.]
I feel compelled to point out here that low pH values are bad for your teeth. Low pH destroys the protective biofilm and leaches phosphorus and the like out of the teeth, weakening them and leading to cavities. I only know this because I recently proofread a dentist’s book all about it. So, like, maybe don’t try to lower your saliva pH to get more zinc.