Okay i shall attempt this: Acetic acid (CH3COOH) is an acid, it forms Hydrogen ions in presence of water:
CH3COOH + H2O
(use the reversible arrow) CH3COO- + H3O+
Now, bone is about 50% Hydroxylapatite, or Ca5(PO4)3(OH), the rest being connective tissue comprising of proteins like Type-I collagen. So since Hydroxylapatite is the main component of a bone's structure, lets look at how acid breaks it down:
Firstly, Hydroxylapatite is highly insoluble, with a Ksp of 6.8x10^-37. This means that the concentration of the following ions (as indicated by square brakets) must be below that of Ksp in order for bone to dissolve:
[Ca2+]^5[PO43-]^3[OH-] = Ksp (at saturation point of Hydroxylapatite)
The reaction of dissolving Hydroxylapatite is as follows:
Ca5(PO4)3(OH) ---> (use the reversible arrow) 5Ca2+ + 3PO43- + OH-
When acid is added it does 2 things.
1. It reacts with the OH- to form H2O, shifting the equilibrium rightward and more Hydroxylapatite is dissolved
2. It reacts with the phosphate ions formed:
H3O+ + PO43-
H2O + HPO42
H3O+ + HPO42-
H2O + H2PO4-
This is because the first proton of acetic acid is stronger than that of the second proton of Phosphoric acid.
This consumes the Phosphate ions produces from the solution of Hydroxylapatite, also shifting the equilibrium rightward
These reactions continue until the acid is neutralised. Also, note that the products of the reaction, Ca(H2PO4)2, is much more soluble compared to the starting bone material, Ksp of Ca(H2PO4)2 is about 1.0x10^-3
And that, is the wonderful way the human body reduces its acidity, its called calcium bleaching.
Thats why vegans argue that vegetables are healthier, their digestion and metabolism does not produce ketonic acids which would leach our bones.
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