Calculate the pH of a solution prepared by mixing 0.080 0 mol of chloroacetic acid plus 0.040 0 mol of sodium chloroacetate in 1.00 L of water.

Respuesta :

Explanation:

The given data is as follows.

        Moles of chloroacetic acid = 0.08 mol

        Moles of sodium chloroacetate = 0.04 mol

So, first calculate the molarity of chloroacetic acid and sodium chloroacetate as follows.

         Molarity = [tex]\frac{\text{no. of moles}}{\text{volume in liter}}[/tex]

Molarity of chloroacetic acid = [tex]\frac{\text{no. of moles}}{\text{volume in liter}}[/tex]

                               = [tex]\frac{0.08 mol}{1.00 L}[/tex]

                               = 0.08 M

 Molarity of sodium chloroacetate = [tex]\frac{\text{no. of moles}}{\text{volume in liter}}[/tex]

                               = [tex]\frac{0.04 mol}{1.00 L}[/tex]

                               = 0.04 M    

Now, according to the Henderson-Hasselbalch equation,

         pH = [tex]pK_{a} + log(\frac{\text{base}}{\text{acid}})[/tex]

               = [tex]pK_{a} + log{\frac{[salt]}{[acid]}}[/tex]

               = [tex]2.865 + log \frac{0.04}{0.08}[/tex]

              = 2.564

Thus, we can conclude that pH of given solution is 2.546.