Question

Toxic Cr(VI) can be precipitated from an aqueous solution by bubbling SO2 through the

Answer 1

Answer:

2.48 × 10⁴ mol

Explanation:

Step 1: Write the balanced equation

2 CrO₄²⁻ + 3 SO₂ + 4 H⁺ ⇒ Cr₂(SO₄)₃ + 2 H₂O

Step 2: Calculate the reacting moles of CrO₄²⁻

3.00 × 10⁸ L of 5.50 × 10⁻² mM CrO₄²⁻ react. The reacting moles are:

3.00 × 10⁸ L × 5.50 × 10⁻² × 10⁻³ mol/L = 1.65 × 10⁴ mol

Step 3: Calculate the reacting moles of SO₂

The molar ratio of CrO₄²⁻ to SO₂ is 2:3. The reacting moles of SO₂ are 3/2 × 1.65 × 10⁴ mol = 2.48 × 10⁴ mol.