Final answer:
Ka for lactic acid in a 1.00 M aqueous solution with 2.94% ionization is calculated to be 8.9 × 10^-4 by using the dissociation formula considering hydronium and lactate ions concentration to be equal and subtracting the dissociated amount from the initial concentration of lactic acid to find the concentration of undissociated acid.
Step-by-step explanation:
During strenuous exercise, lactic acid builds up in muscle tissues and partially ionizes in solution. The degree of ionization can be represented by the acid dissociation constant (Ka). Given a 1.00 M solution where 2.94% of lactic acid is ionized, we can determine the Ka value.
To find Ka, we'll use the formula Ka = [H+][A-]/[HA], where [H+] is the concentration of hydronium ions, [A-] is the concentration of the lactate ion and [HA] is the concentration of undissociated lactic acid.
In a 1.00 M solution with 2.94% ionization, the concentration of ionized lactic acid is 0.0294 M. Since the reaction produces equal amounts of hydronium ions and lactate ions, we have [H+] = [A-] = 0.0294 M, and the concentration of undissociated lactic acid [HA] is 1.00 M - 0.0294 M = 0.9706 M.
Substitute these values into the equation to get the Ka value:Ka = 8.9 × 10-4.