Question

Why do we assume 100% ionization for acetic acid (a weak acid)? This is a titration problem. The titrant is sodium hydroxide, if that helps.

Answer 1

Acetic acid IS, by all means, a weak acid. It does not ionize completely but only about 1% or so depending upon the concentration. My assumption about your question is that as acid is titrated with NaOH that the acid becomes weaker and weaker. At weaker concentrations it ionizes more than that and at the end has completely ionized.
Try this exercise.
% ionization 0.1M acetic acid. I get 1.3%.
% ionization 0.001 M acetic acid is 13%
I didn't do it for less but you get the picture. When you get to 1 drop before the end point it is essentially 100% ionized.

Answer 2

Thx poutana

Answer 3

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