A 50.00 mL 1.5 M of NaOH titrated with 25.00 ml of H_3PO_4 (aq). What is the concentration of the is H_3PO_4 solution?

1 Answer
Aug 2, 2017

[H_3PO_4]-=1.50*mol*L^-1

Explanation:

We follow the stoichiometric reaction......

H_3PO_4(aq) + 2NaOH(aq) rarr Na_2HPO_4(aq) + 2H_2O(l)

And it is a fact that phosphoric acid acts as DIACID in aqueous solution. Na_3PO_4 WILL NOT BE ACCESSED even at high pH.

"Moles of NaOH"=50.00xx10^-3Lxx1.5*mol*L^-1=0.075*mol.....

And thus, with respect to H_3PO_4, there was a (0.075*mol)/2 molar quantity.......

And [H_3PO_4]=((0.075*mol)/2)/(25.00*mLxx10^-3*L*mL^-1)

=(0.075*mol)/2 of course, we might have been able to nut this result out directly, had we been on the ball in the first instance.