Ask Question
1 May, 23:03

Many important biochemicals are organic acids, such as pyruvic acid (p K a = 2.50) and lactic acid (p K a = 3.86). The conjugate bases are pyruvate and lactate, respectively. For each acid, determine which form-the acid or the conjugate base-predominates at pH 7.4. A graphic shows a check mark inscribed on a colored circle. 6

+3
Answers (1)
  1. 2 May, 02:25
    0
    Pyruvic acid: conjugate base

    Lactic acid: conjugate base

    Explanation:

    The ratio of conjugate base to conjugate acid can be found using the Henderson-Hasselbalch equation when the pH and pKa are known.

    pH = pKa + log ([A⁻]/[HA])

    The equation can be rearranged to solve for the ratio:

    pH - pKa = log ([A⁻]/[HA])

    [A⁻]/[HA] = 10^ (pH-pKa)

    Now we can calculate the ratio for the pyruvic acid:

    [A⁻]/[HA] = 10^ (pH-pKa) = 10^ (7.4 - 2.50) = 79433

    [A⁻] = 79433[HA]

    There is a much higher concentration of the conjugate base.

    Similarly for lactic acid:

    [A⁻]/[HA] = 10^ (pH-pKa) = 10^ (7.4 - 3.86) = 3467

    [A⁻] = 3467[HA]

    For lactic acid the conjugate base also dominates at pH 7.4
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “Many important biochemicals are organic acids, such as pyruvic acid (p K a = 2.50) and lactic acid (p K a = 3.86). The conjugate bases are ...” in 📙 Chemistry if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers