Question

A 1.340gram sample of an unknown acid, H3A, was placed in a 250.0 mL volumetric flask and diluted
to volume with water. A 45.35 mL sample of this acid solution was titrated with 37.77 mL of a
0.1006M NaOH solution.

A) Using one set - up dimensional analysis
B) Calculate the molar mass of this unknown acid

I do not know how to start...

Answer 1

Technically we can't do this because you don't specify an indicator; therefore, we don't know how many of the H ions were titrated. I will assume we titrated all 3.
H3A + 3NaOH ==> 3H2O + Na3A

mols NaOH = M x L = ?
Then ? mols NaOH x (1 mol H3A/3 mols NaOH) = mols NaOH/3
Finally, mols H3A = grams/molar mass. You know mols H3A and grams H3A, solve for molar mass H3A.