The experimental data from an acid-base titration can be used to calculate the moles of base used and the moles of ionizable protons (H⁺) present in the unknown.

The formula M x V_L = moles can be used for calculating the moles of acid or base provided the reaction stoichiometry is 1:1 (a monoprotic acid).

In a titration experiment, 5.68 mL of an unknown base is titrated with 0.3467 M HCl. A volume of 15.89 mL of the acid is required to reach the phenolphthalein endpoint,

How many moles of HCl were used in the titration?

Enter only the numerical value - the units, moles, are not required.