Calculate amount (in grams) of unknown acid used for titration. You want 30 mL of titrant to get the equivalence point. Assume that the base is 0.05 M and the unknown acid molar mass is around 400 g/mol.

Answer 1

millimoles base 0.05M x 30 mL = about 1.5 = 0.0015 mols.
mols acid = 0.0015.
mol = grams acid/molar mass acid. You know molar mass and mol; solve for grams.