Chemistry - Redox Reactions Question with Solution | TestHub

P₄O₁₀ + 6H₂O $\to$ 4H₃PO₄. Moles P₄O₁₀ = 5.68/284 = 0.02, so H₃PO₄ = 0.08 mol in 250 ml = 0.32 M: (a) true. (b) 25 ml has 8 mmol H₃PO₄; complete neutralization needs 24 mmol NaOH = 48 ml x 0.5 M - true. (c) 15 ml has 4.8 mmol phosphate; 2H₃PO₄ + 3BaCl₂ $\to$ Ba₃(PO₄)₂ needs 7.2 mmol BaCl₂ = 36 ml x 0.2 M - true. (d) 40 ml has 12.8 mmol; first equivalent point (to NaH₂PO₄) needs 12.8 mmol = 12.8 meq KOH $\to$ 16 ml of 0.8 N, not 48 ml - false. Hence (a), (b), (c).