I'm struggling with this homework question...i have no idea how to set this up.

We start with a 33.50 mL aliquot of acetic acid and titrate it with 0.215 M of NaOH. Find the pH
at:

21.7 ML added

the equivalence point

i don't understand how this works. please help, thank you.

NaOH + CH3COOH ==> CH3OONa + HOH

I believe you need the concn of acetic acid to continue.