I think it’s A because each unit is worth 3
Triprotic acid is a class of Arrhenius acids that are capable of donating three protons per molecule when dissociating in aqueous solutions. So the chemical reaction as described in the question, at the third equivalence point, can be show as: H3R + 3NaOH ⇒ Na3R + 3H2O, where R is the counter ion of the triprotic acid. Therefore, the ratio between the reacted acid and base at the third equivalence point is 1:3.
The moles of NaOH is 0.106M*0.0352L = 0.003731 mole. So the moles of H3R is 0.003731mole/3=0.001244mole.
The molar mass of the acid can be calculated: 0.307g/0.001244mole=247 g/mol.
Answer:

Explanation:
Hello,
In this case, since hydrochloric acid and barium hydroxide are in a 2:1 molar ratio, for the neutralization, the following moles equality must be obeyed:

In such a way, in terms of molarities and volumes, we can compute the required volume of hydrochloric acid as shown below:

Besr regards.
The answer is volume that is volume limits the precision of data obtained in an experiment .
As while pouring of the liquids, we control the volume, but it can have been off. And this could results in the wrong mole to mole ratio.Thus it limits the precision, So the answer is that volume limits the precision of data obtained in an experiment .
I think because each element has its own number of protons and neutrons, giving it its own atomic number and mass (correct me if I’m wrong please)