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

215.0mL of Ba(OH)2 is needed to completely neutralize the acid, determine the concentration
of the Ba(OH)2 solution used

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
solve for molarity of base

0.927 mol/L

0.937

To determine the concentration of the Ba(OH)2 solution used, we need to calculate the number of moles of H3PO4 in the liquid sample and then use the stoichiometry of the balanced equation between H3PO4 and Ba(OH)2 to find the number of moles of Ba(OH)2.

Here's how we can calculate it step by step:

1. Calculate the number of moles of H3PO4 in the liquid sample.
- We are given that the sample contains 17.5% by mass of H3PO4.
- Therefore, the mass of H3PO4 in the sample can be calculated as:
Mass of H3PO4 = (17.5/100) * mass of the sample
= (17.5/100) * 75.0g
= 13.125g

- Next, we need to convert the mass of H3PO4 into moles. To do this, we divide the mass by the molar mass of H3PO4:
Moles of H3PO4 = Mass of H3PO4 / molar mass of H3PO4
= 13.125g / 98.0g/mol

2. Use the stoichiometry of the balanced equation between H3PO4 and Ba(OH)2 to find the number of moles of Ba(OH)2.
- The balanced equation is:
2H3PO4 + 3Ba(OH)2 → Ba3(PO4)2 + 6H2O

- From the balanced equation, we can see that 2 moles of H3PO4 react with 3 moles of Ba(OH)2.
- Since we have calculated the moles of H3PO4 in step 1, we can calculate the moles of Ba(OH)2 needed as:
Moles of Ba(OH)2 = (Moles of H3PO4 / 2) * (3 / 1)

3. Calculate the concentration of the Ba(OH)2 solution used.
- The given volume of Ba(OH)2 solution is 215.0 mL.
- To calculate the concentration, we need to convert the volume from mL to L:
Volume of Ba(OH)2 solution in L = 215.0 mL / 1000

- Finally, we can calculate the concentration as:
Concentration of Ba(OH)2 solution = Moles of Ba(OH)2 / Volume of Ba(OH)2 solution in L

Plug in the values obtained in steps 1 and 2 to calculate the concentration of the Ba(OH)2 solution used.

0.00092mol/L