Lactic acid C_3H_6O_3 is found in sour milk where it is produced by the action o
ID: 1050023 • Letter: L
Question
Lactic acid C_3H_6O_3 is found in sour milk where it is produced by the action of lactobacilli in lactose or the sugar in milk. The pH of a 0.025 M solution of lactic acid was determined using a pH probe and found to be 2.75. Calculate the equilibrium constant for this acid. Had you not been given the pH of the acid and you had to measure it yourself, how would the method in part 2 be applied to the determination of Ka? Would you expect an improvement in the accuracy of your result with the application of the method of this experiment? Explain why or why not.Explanation / Answer
4a
ph =2.75
[H+] = 10^-pH = 10^-2.75
HA = 0.025 M
so..
in equilibrium
[H+] =[A-] = 10^-2.75
[HA] = 0.025 -10^-2.75
Ka = [H+][A-]/[HA]
Ka = (10^-2.75)(10^-2.75) / (0.025 - 10^-2.75)
Ka = 0.00013617
Ka = 1.36*10^-4
b)
if you measure pH, this should be more accurate value than a theoretical
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.