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An aqueous solution contains 0.453 M Na2HPO4 and 0.167 M H2PO4-. The pH of this solution is .
An aqueous solution contains 0.453 M Na2HPO4 and 0.167 M H2PO4-. The pH of this solution is .?
回答 (1)
2018-03-09 1:43 pm
Refer to: http://clas.sa.ucsb.edu/staff/Resource%20folder/Chem109ABC/Acid,%20Base%20Strength/Table%20of%20Acids%20w%20Kas%20and%20pKas.pdf
The second dissociation of H₃PO₄, Kₐ₂ = 6.23 × 10⁻⁸ and pKₐ₂ = 7.21
H₂PO₄⁻(aq) ⇌ HPO₄²⁻(aq) + H⁺(aq) …… pKₐ₂ = 7.21
Henderson-Hasselbach equation:
pH = pKₐ₂ + log([HPO₄²⁻]/[ H₂PO₄⁻]) = 7.21 + log(0.453/0.167) = 7.64
The second dissociation of H₃PO₄, Kₐ₂ = 6.23 × 10⁻⁸ and pKₐ₂ = 7.21
H₂PO₄⁻(aq) ⇌ HPO₄²⁻(aq) + H⁺(aq) …… pKₐ₂ = 7.21
Henderson-Hasselbach equation:
pH = pKₐ₂ + log([HPO₄²⁻]/[ H₂PO₄⁻]) = 7.21 + log(0.453/0.167) = 7.64
收錄日期: 2021-04-24 01:04:45
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