a 30.0ml sample of diprotic acid is titrated with .260M KOH. if 68.5ml is required to reach the equivalence point, what is the concentration of the acid?

Answer 1

H2A + 2KOH ==> K2A + 2H2O

moles KOH = M x L = ?
Convert moles KOH to moles H2A using the coefficients in the balanced equation. moles H2A = 1/2 mole KOH.

Then M H2A = moles H2A/L H2A. Solve for L and convert to mL.