To get the ratio of the concentration of sodium acetate to the concentration of acetic acid we are going to use H-H equation:
when:
PH = Pka + ㏒[salt/acid]
when the Ka of acetic acid = 1.75 x 10^-5
so, we can get Pka from this formula:
Pka = -㏒Ka
= -㏒1.75 x 10^-5
= 4.76
and when we have PH = 5.75, so by substitution:
∴ 5.75 = 4.76 + ㏒[acetate/ acetic acid]
∴ [acetate/acetic acid] = 9.77
∴ the ratio of a concentration of acetate to acetic acid 9.77
