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Titration is a technique in which a solution of known concentration (the titrant) is used to determine the concentration of an analyte (the titrand) in another solution. In an acid-base titration, a strong base is added to a weak acid or vice versa to neutralize the solution gradually. The equivalence point is the point during titration when the amount of added titrant is stoichiometrically equivalent to the amount of analyte in the initial solution.

A weak monoprotic acid is an acid that donates one proton (\(\mathrm{H^+}\)) per molecule but does not ionize completely in water, meaning the equilibrium between the ionized and unionized forms lies significantly on the side of the molecular (unionized) form. Examples of weak monoprotic acids include acetic acid (CH3COOH), formic acid (HCOOH), and HF. On the other hand, strong bases are chemical species that are fully ionized in water, producing a high concentration of hydroxide ions (\(\mathrm{OH^-}\)). Examples of strong bases include sodium hydroxide (NaOH) and potassium hydroxide (KOH).

At the equivalence point, the weak acid has reacted completely with the strong base, resulting in a solution of the conjugate base of the weak acid and the cation from the strong base. For example, in a titration of acetic acid with sodium hydroxide, the resulting solution at the equivalence point will be a solution of sodium acetate (CH3COONa) and water (H2O). The pH of the solution at the equivalence point depends on the ionization of the conjugate base (i.e., how readily it accepts a proton) in water. The ionization of the conjugate base produces hydroxide ions, raising the pH of the solution. The basicity of the conjugate base varies depending on the original acid and its pKa value. Therefore, the pH at the equivalence point will be affected by the nature of the weak monoprotic acid used in the titration.

As we saw in the previous step, the nature and basicity of the conjugate base formed at the equivalence point affect the pH of the solution. Since different weak monoprotic acids have different pKa values and varying basicities of their conjugate bases, the pH at the equivalence point will also vary for different acid-base pairs. To summarize, no, not all titrations of samples of weak monoprotic acids with solutions of strong bases have the same pH at their equivalence points due to the varying basicities of the conjugate bases formed at the equivalence points.