If a 95.27 mL sample of acetic acid (HC2H3O2) is titrated to the equivalence point with 79.06 mL of 0.113 M KOH, what is the pH of the titration mixture? (For HC2H3O2 , Ka = 1.82 x 10-5)

8.73

Explanation:

The concentration of acetic acid can be determined as follows:

Moles of =

=0.0090 moles

Moles of  

= 0.0090 moles

The equation for the reaction can be expressed as :

              ----->                

Concentration of ion =

=

= 0.052 M

Hydrolysis of   ion:

                 ----->                

⇒    

=    

As K is so less, then x appears to be a very infinitesimal small number

0.052-x ≅ x

pH = 14 - pOH

pH = 14 - 5.27

pH = 8.73

Hence, the pH of the titration mixture = 8.73