2. A 25.00 mL sample of an unknown monoprotic weak acid is titrated to the equivalence point with 14.65 mL of 0.09861 M NaOH. Calculate the concentration of the unknown weak acid. Solution at equalent point no of moles of weak acid = no of moles of base M1V1 = M2V2 HA is mono protic acid HA + NaOH ---------------> NaA + H2O HA NaOH M1 = M2 = 0.09861M V1 = 25ml V2 = 14.65ml M1V1 = M2V2 M1 = M2V2/V1 = 0.09861*14.65/25 = 0.058 M The concentration of the unknown weak acid is 0.058M.