Question 54

Only 2 mL of KMnO₄ solution of unknown molarity is required to reach the end point of a titration of 20 mL of oxalic acid (2M) in acidic medium. The molarity of KMnO₄ solution should be ______ M.

Correct Answer: 8

The reaction: 2KMnO₄ + 5H₂C₂O₄ + 3H₂SO₄ → 2MnSO₄ + K₂SO₄ + 10CO₂ + 8H₂O

Mole ratio: KMnO₄ : H₂C₂O₄ = 2 : 5

Moles of oxalic acid = 0.020 × 2 = 0.04 mol

Moles of KMnO₄ = (2/5) × 0.04 = 0.016 mol

Molarity of KMnO₄ = 0.016/0.002 = 8 M

The answer is 8.

Create a FREE account and get:

Download resources