A quantity of 5.68 g of pure P 4 O 10 is dissolved completely in sufficient water and the solution is diluted to 250 ml . Which of the following statement is incorrect? ( P = 31 )

Question

A quantity of 5.68 g of pure P 4 ​ O 10 ​ is dissolved completely in sufficient water and the solution is diluted to 250 ml . Which of the following statement is incorrect? ( P = 31 )

TestHub · Accepted Answer

Reaction: P₄O₁₀ + 6H₂O → 4H₃PO₄.

Moles of P₄O₁₀ = $\frac{5.68 g}{284 g / m o l} = 0.02 m o l$ , yielding $0.08 m o l$ of H₃PO₄.

Molarity: Molarity of H₃PO₄ = $\frac{0.08 m o l}{0.25 L} = 0.32 M$ (Statement A is correct).

First Equivalence Point (D): $40 m l$ of H₃PO₄ contains $40 \times 0.32 = 12.8 mm o l$ , which requires exactly $12.8 mm o l$ of KOH since the n-factor is $1$ .

Incorrect Statement: The given KOH equals $48 m l \times 0.8 N = 38.4 mm o l$ , which is incorrect. Thus, the answer is (D).

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