Tartaric Acid is C4H6O6
8.7ml of 0.0511mol/L NaOH = 4.4567x10^-4 moles.
Since NaOH is monoprotic (1 mole of OH per mole of NaOH)
and tartaric acid is diprotic,
1 mole of tartaric acid neutralises 2 moles of NaOH
As you used 4.4567x10^-4 moles of NaOH , that means in the wine, there was only...