ANSWER -
The balanced chemical equation for the reaction between perchloric acid (HClO4) and barium hydroxide (Ba(OH)2) is:
2HClO4 + Ba(OH)2 → Ba(ClO4)2 + 2H2O
We can see that the reaction requires two moles of perchloric acid for every one mole of barium hydroxide.
First, we can calculate the number of moles of barium hydroxide used:
moles of Ba(OH)2 = Molarity × volume in liters
moles of Ba(OH)2 = 0.02486 M × 0.01375 L
moles of Ba(OH)2 = 0.000341725
From the balanced equation, we know that two moles of perchloric acid react with one mole of barium hydroxide. Therefore, the number of moles of perchloric acid in the solution is:
moles of HClO4 = 0.000341725 mol Ba(OH)2 × (2 mol HClO4 / 1 mol Ba(OH)2)
moles of HClO4 = 0.00068345
Finally, we can calculate the molarity of the perchloric acid solution:
Molarity = moles of solute / volume of solution in liters
Molarity = 0.00068345 mol / 0.02000 L
Molarity = 0.03417 M
Therefore, the molarity of the perchloric acid solution is 0.03417 M.