Question

Use the calculated pKa to determine the pH at which [CH₃COOH]=[CH₃COO−].

A. pKa = 4.75
B. pKa = 5.25
C. pKa = 9.75
D. pKa = 10.25

Answer 1

The pH at which [CH₃COOH]=[CH₃COO−] can be determined by comparing the pKa value of the acid with the pH range in which the ratio [A-]/[HA] is between 1 and 10.

Step-by-step explanation:

The pH at which [CH₃COOH]=[CH₃COO−] can be determined by comparing the pKa value of the acid with the pH range in which the ratio [A-]/[HA] is between 1 and 10. In this case, the correct pKa value is 4.75 (Option A). Therefore, the pH at which the concentrations of acetic acid and acetate ions are equal is between the pKa value (4.75) and pKa + 1, or between 4.75 and 5.75.