Question

A 75.0g sample of liquid contains 17.5% by mass of H3PO4 (molar mass = 98.0g/mol). If

Answer 1

assuming no other acid is in the H3PO4 mix, then 
a) the equation 
2H3PO4 + 3Ba(OH)2>>3H2O+Ba3(PO3)2 

titration equation: 
nb*Ma*Va=na*Mb*Vb 
nb*molesacid=na*molesbase 
3*75*.175/98=2*Molaritybase*.215 
0.927 mol/L