Question

The ph of a solution containing 0.818 M acetic acid (ka1.76*10-5) ans 0.172 M sodium acetate is?

Answer 1

Explanation:

It is known that the relation between pH and $pK_{a}$ is as follows.

              pH = $pK_{a} + log \frac{[salt]}{[acid]}$

and,     $pK_{a} = -log K_{a}$

Hence, first we will calculate the value of $pK_{a}$ as follows.

                   $pK_{a} = -log K_{a}$

                               = $-log (1.76 \times 10^{-5}$

                               = 4.75

Now, we will calculate the value of pH as follows.

              pH = $pK_{a} + log \frac{[\text{sodium acetate}]}{\text{acetic acid}}$

                    = $4.75 + log \frac{0.172}{0.818}$      

                    = 4.75 + (-0.677)

                    = 4.07

Therefore, we can conclude that the pH of given solution is 4.07.