Respuesta :

The Henderson-Hasselbalch equation is:

[tex]pH = pK_a + log \frac{[conjugate base, (A^{-})]}{[weak acid, (HA)]}[/tex]

From the above equation.,

  • When concentration of both the forms that is the concentration of conjugate base and weak acid are equal then pH = [tex]pK_a[/tex].

[tex][conjugate base, (A^{-})] = {[weak acid, (HA)]}[/tex]

[tex]pH = pK_a + log \frac{[weak acid, (HA)]}{[weak acid, (HA)]}[/tex]

[tex]pH = pK_a + log 1[/tex]

[tex]pH = pK_a[/tex]

  • When pH < [tex]pK_a[/tex], protonated species.
  • When pH > [tex]pK_a[/tex], deprotonated species.

pH of [tex]CH_3COOH[/tex] is 10 and [tex]pK_a[/tex] is 4.8. (given).

Since, pH > [tex]pK_a[/tex] so, deprotonated form of [tex]CH_3COOH[/tex] will be predominant that is [tex]CH_3COO^{^{-}}[/tex].

The structure of the predominant form of [tex]CH_3COOH[/tex]  is shown in the image.

Ver imagen Mergus
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