A sample of P₄O₁₀ is dissolved in water to form phosphoric acid. If 14.2 g of P₄O₁₀ is used, how many ml of 2 M NaOH are needed to completely neutralize the resulting acid to form Na₂HPO₄?
- 100
- 200
- 300
- 400
📝 Detailed explanation
P₄O₁₀ + 6H₂O → 4H₃PO₄.Moles P₄O₁₀ = 14.2 / 284 = 0.05 mol.
Moles H₃PO₄ = 0.05 × 4 = 0.2 mol.
H₃PO₄ + 2NaOH → Na₂HPO₄ + 2H₂O.
Moles NaOH = 0.2 × 2 = 0.4 mol.
Volume NaOH = 0.4 / 2 = 0.2 L = 200 ml.
Wait, let's check P₄O₁₀ mass again: 14.2/284=0.05.
Correct volume is 200 ml.