A solution at pH 7 contains a weak acid, HA. The pK_a of the acid is 6.5. What is the ratio of [A⁻]:[HA]?

Name: A solution at pH 7 contains a weak acid, HA. The pK a of the acid is 6.5. What is the ratio of [A − ]:[HA]?
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Quizplus · Accepted Answer

At pH 7, which is higher than the pK_a of 6.5, the weak acid HA will be more deprotonated, resulting in a higher concentration of A⁻ than HA. Using the Henderson-Hasselbalch equation, the ratio [A⁻]:[HA] is approximately 3:1.

A Solution at PH 7 Contains a Weak Acid, HA