A #17.15*mL# volume of phosphoric acid of #0.077*mol*L^-1# concentration reacts with how many grams of sodium hydroxide to reach stoichiometric equivalence?
Phosphoric acid acts as a diacid in water, and thus we interrogate the stoichiometric reaction:
And so at the endpoint we have
And thus moles of
And this reacts with TWICE this molar quantity of