Potassium hydrogen phthalate khp is used to standardize

Question

Potassium hydrogen phthalate (KHP) is used to standardize sodium hydroxide. If 52.4 mL of NaOH(aq) is required to titrate 0.643 g KHP to the equivalence point, what is the concentration of the NaOH(aq)? (The molar mass of KHP = 204.2 g/mol)

HC₈H₄O₄^-(aq) + OH^-(aq)  C₈H₄O₄^2-(aq) + H₂O()