Calculate the H3O+concentration at the equivalence point. (Ka CH3COOH = 1.8 × 10−5).?

10.00 mL of 0.101 M acetic acid was diluted with distilled water to 40.00 mL and titrated with 0.100 M NaOH. Calculate the H3O+concentration at the equivalence point. (Ka CH3COOH = 1.8 × 10−5).