Question

If 0.50 moles of NaOH were added to reach the equivalence point in a titration how many miles of tartaric acid reacted?

Answer 1

Tartaric acid has two ionizable H^+ but k1 is very close to k2; I assume the 0.50 mols reduced both and that's the equivalence point to which you refer.
H2T + 2NaOH ==> Na2T + 2H2O
0.5 mol NaOH x (1 mol H2T/2 mols NaOH) = 0.5 x 1/2 = 0.25 mols H2T