Acid_Base equilibria; How do I calculate molarities with one species given?

Question

Formic acid (HCO2H, Ka = 1.8 × 10-4) is the principal component in the venom of stinging ants. What is the molarity of a formic acid solution if 25.00 cm3 of the formic acid solution requires 29.80 cm3 of 0.0567 M NaOH to reach the equivalence point?

Answer 1

Moles NaOH = Molarity x Volume ( in Liters) =

= 0.02980 L x 0.0567 M =  0.00169

NaOH + HCOOH >> HCOONa + H2O

Moles HCOOH = 0.00169

M = moles / V = 0.00169 mol / 0.02500 L =  0.0676 M