You Need to Use KH₂PO₄ and K₂HPO₄ to Prepare a Buffer

question 32

Multiple Choice

You need to use KH₂PO₄ and K₂HPO₄ to prepare a buffer with a pH of 7.45. Which of the following ratios of [base]/[acid] is required? For phosphoric acid, (H₃PO₄) , K_a2 = 6.2 × 10⁻⁸.

• A)[base]/[acid] = 1.75
• B)[base]/[acid] = 1.27
• C)[base]/[acid] = 1.24
• D)[base]/[acid] = 0.79
• E)[base]/[acid] = 0.57

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