Is there any acid with pH 0?If there is, what is it?

Question

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Answer 1

The pH is a function of the specific acid and its concentration.

A pH of 0 indicates that the concentration of hydrogen ions is 1 mol/L.

For instance, HCl is a strong acid, so HCl at a concentration of 1 mol/L will have a pH of 0. So will H2SO4 at a concentration of 1.0 mol/L (not 0.5 mol/L as you might expect; only the first hydrogen ion dissociates readily in water, though both will react if you add a base). In general, any strong acid at a concentration of 1.0 mol/L will give you a pH of 0.

However, weak acids cannot achieve a pH of 0 under normal conditions. For instance, hydrofluoric acid (about the strongest weak acid) has a Ka of about 7.1×10^-4. This means that in the equilibrium
HF -> H+(aq) + F-(aq)
we have [H+] . [F-] / [HF] = 7.1×10^-4
If we want a pH of 0, so [H+] = 1.0 mol/L, then we must have [F-] = [H+] and so [HF] = 1 / (7.1×10^-4) = 1.4×10^3 mol/L. However pure liquid HF, which has the same density as water and a molar mass of 20.0, can only be concentrated to (1000/20.0) = 50 mol/L.

Answer 2

YES. If the pH is zero, then the concentration of the acid is 10^0 or just 1 Molar. It is any acid with molarity of 1 M.