Question Detail
Question
A 20.00 mL sample of an H₃PO₄ solution is titrated with 35.00 mL of a 0.100 M NaOH solution. What is the concentration of the H₃PO₄ solution?
Correct Answer
Option A is the correct answer.
Detailed Explanation
Balanced equation: H₃PO₄ + 3NaOH → Na₃PO₄ + 3H₂O. Moles NaOH = 0.03500 L × 0.100 M = 0.003500 mol. Moles H₃PO₄ = 0.003500/3 = 0.001167 mol. Molarity H₃PO₄ = 0.001167/0.02000 = 0.05835 M ≈ 0.0583 M.
Hint
The mole ratio is 1:3 for H₃PO₄ to NaOH.