Final answer:
The pKa of lactic acid can be calculated using the Henderson-Hasselbalch equation with the given concentrations of lactic acid and lactate, along with the pH of the solution.
Step-by-step explanation:
To calculate the pKa of lactic acid, you can use the Henderson-Hasselbalch equation, which is pH = pKa + log([A-]/[HA]), where [A-] is the concentration of the conjugate base (lactate) and [HA] is the concentration of the acid (lactic acid). Given the pH is 4.8, [A-] is 0.087 M, and [HA] is 0.01 M, we can rearrange the equation to solve for pKa: pKa = pH - log([A-]/[HA]). By substituting the given values into the equation, we get pKa = 4.8 - log(0.087/0.01), which can be calculated using a calculator.
After performing the calculation, you would get the pKa of lactic acid which is the negative logarithm (base 10) of the acid dissociation constant (Ka). If you had the Ka value, you could directly calculate pKa by using the formula pKa = -log(Ka). Conversely, if you have the pKa, you can find the Ka by calculating 10 raised to the power of the negative pKa (Ka = 10^(-pKa)).