2 L of 0.2 M H₂SO₄ is reacted with 2 L of 0.1 M NaOH solution, the molarity of the resulting product Na₂SO₄ in the solution is _____ millimolar. (Nearest integer).
Answer: 25
Solution
The reaction is: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O. Initial moles: H₂SO₄ = 0.2 × 2 = 0.4 mol; NaOH = 0.1 × 2 = 0.2 mol. Since 1 mol H₂SO₄ requires 2 mol NaOH, 0.2 mol NaOH will react with 0.1 mol H₂SO₄, producing 0.1 mol Na₂SO₄. Total volume = 4 L. Molarity of Na₂SO₄ = 0.1/4 = 0.025 M = 25 mM.
JEE Main · 2022 · 28 Jul 2022 · Shift 2 · Integer answer