5158. 20% oleum means that in 100 kg oleum, there are 20 kg of September 7, 2025 by Admin SO₃ and 80kg of H₂SO₄ H₂SO₄ and 80kg of SO₃ SO₃ for each 100 kg of H₂SO₄ None of these ✅ The correct answer is option A.
