If an Aqueous Solution Is Prepared by Dissolving 1

question 106

Multiple Choice

If an aqueous solution is prepared by dissolving 1.6 mol Na₂CrO₄ in 1.0 L of a buffer at pH 8.24,what will be [Cr₂O₇^2-] in the solution? The resultant equilibria are:
HCrO₄^-(aq) ⇌ H⁺(aq) + CrO₄^2-(aq) K_a = 3.2 × 10^-7
2 HCrO₄^-(aq) ⇌ Cr₂O₇^2-(aq) + H₂O(l) K = 33

• A)9.9 × 10^-5 M
• B)2.9 × 10^-28 M
• C)8.9 × 10^-9 M
• D)8.6 × 10² M
• E)2.8 × 10^-2 M

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