Respuesta :
Answer:
The answer to this problem is the lactate to lactic acid ratio is approximately 7:1. , for detailed steps on how to go about the answer, please see below
Explanation:
From the question. pH of the solution =3.05
pH being the concentration of [H3O+] in the solution, [H3O+] can be calculated by
pH=−log10[H3O+] hence [H3O+]= [tex]10^{-pH}[/tex]
which is = [tex]10^{-3.05}[/tex] = 8.91×[tex]10^{-4}[/tex]mol×dm−3
That is the concentration of H3O+, [H3O+] is approximatley 8.91×[tex]10^{-4}[/tex]mol×dm−3 as
When lactic acid dissociates, it forms one oxonium ion,[H3O+], and one lacate ion that is there are equal number of moles of oxonium ion and lacate ion in the solution hence [H3O+]=[lactate]
The Ka of the lactic cid can be found by pKa = -LogKa
or Ka = [tex]10^{-pKa}[/tex] = [tex]10^{-3.86}[/tex] = 1.34 × [tex]10^{-4}[/tex]mol×dm−3
The Ka equation is given by
Ka=[tex]\frac{[H3O+][lactate]}{[Lactic.]}[/tex]
Since the concentration of the oxonium ion and the lactate ion are equal
[H3O+]=[lactate]
we have
(1.34 × [tex]10^{-4}[/tex])=(8.91×[tex]10^{-4}[/tex])²÷ x
where x = lactic acid concentration
Hence
x=[Lactic]=(8.91×[tex]10^{-4}[/tex])² ÷ (1.34 × [tex]10^{-4}[/tex]) =5.92×10^(-3)
Therefore the
[Lactate]/[Lactic]=5.92×10^(-3)/8.91×[tex]10^{-4}[/tex]≈6.65 ≈ 7
The concentration of lactate is approximately 7 times higher than the concentration of lactic acid, therefore the lactate to lactic acid ratio is approximately 7:1.
