Today I stumbled across a website which defined the titration of weak acid and strong base as the following:
"The titration of a weak acid with a strong base involves the direct transfer of protons from the weak acid to the hydoxide ion. The reaction of the weak acid, acetic acid, with a strong base, NaOH, can be seen below. In the reaction the acid and base react in a one to one ratio." (https://chem.libretexts.org/Ancillary_Materials/Demos_Techniques_and_Experiments/General_Lab_Techniques/Titration/Titration_of_a_Weak_Acid_with_a_Strong_Base)
CH₃COOH + OH⁻→ CH₃COO⁻ + H₂O
But, I clearly remember my professor for analytical chemistry saying that the neutralization of a weak acid and a strong base occurs due to the shift of equilibrium:
CH₃COOH + H₂O → CH₃COO⁻ + H₃O⁺
Where the strong base (NaOH) would continue to remove hydronium ions from the equilibrium, so that more and more of conjugated base, acetate, would form.
So the first part of my question is; what definition is correct?
Furthermore, indeed we usually formulate following equation to approximately quantify the change in concentrations of acid and base:
CH₃COOH + NaOH → CH₃COO⁻ + H₂O + Na+
This way, we find the moles of acid/base and divide by the total volume to get the pH using Hendersson-Hasselbalch equation. But is it correct this way? Are there more accurate methods? The weak acid should dissociate first before being consumed, is that correct?
Anyway, this is not a question about how to calculate the titration curve of this example, rather it is about understanding the nature of the conversion. Thanks in advance!