Answer :
Answer:
pH of the buffer is 3.75
Explanation:
It is possible to find pH of a buffer using Hendersson-Hasselbalch equation:
pH = pKa + log [A⁻] / [HA]
Where [A⁻] is molar concentration of the conjugate base and [HA] concentration of the weak acid
In the lactic buffer, pKa = 3.86. Lactic acid is the weak acid and its conjugate base is tha lactate salt. H-H equation for this buffer is:
pH = 3.86 + log [Lactate] / [Lactic acid]
Replacing with the concentrations of the problem:
pH = 3.86 + log [0.10M] / [0.13M]
pH = 3.75
pH of the buffer is 3.75