Question

Question 5742: 3.15 g of H₂C₂O₄·2H₂O are dissolved in water and made up to a 1.0 dm³ solution. Find the molarity of hydrogen ions.

a) 0.1M
b) 0.05M
c) 0.025M
d) 0.0125M

Answer 1

The molarity of hydrogen ions in the solution is 0.025 M.

Step-by-step explanation:

To find the molarity of hydrogen ions, we need to consider the dissociation of H₂C₂O₄·2H₂O. From the formula, we can see that there are two moles of hydrogen ions (H⁺) for every one mole of H₂C₂O₄·2H₂O. Since we have 3.15 g of H₂C₂O₄·2H₂O, we need to convert it to moles by dividing the mass by the molar mass. The molar mass of H₂C₂O₄·2H₂O is 126.07 g/mol. Therefore, moles of H₂C₂O₄·2H₂O = 3.15 g / 126.07 g/mol = 0.025 mol. Since the solution is 1.0 dm³, the molarity of hydrogen ions is equal to the moles of H₂C₂O₄·2H₂O divided by the volume of the solution in liters. Molarity of H⁺ = 0.025 mol / 1.0 dm³ = 0.025 M.