Acid Strengths
We can measure the relative tendency for acids to donate protons (usually relative to the solvent). Acids are rated from strong to weak.
Strong acid: complete donation of proton to water
HCl(aq) + H2O(l) ? H3O+(aq) + Cl-(aq)
Proton always transfers from the stronger acid to the stronger base to form a weaker acid and a weaker base.