According to Hasselbach-Henderson equation:
Here, is concentration of conjugate base and [HA] is concentration of acid.
In the given problem, conjugate base is and acid is
thus, Hasselbach-Henderson equation will be as follows:
...... (1)
(a) Ratio of concentration of potassium acetate and acetic acid is 2:1 thus,
Also,
Putting the values in equation (1),
Therefore, pH of solution is 5.06.
(b) Ratio of concentration of potassium acetate and acetic acid is 1:3 thus,
Also,
Putting the values in equation (1),
Therefore, pH of solution is 4.28.
(c)Ratio of concentration of potassium acetate and acetic acid is 5:1 thus,
Also,
Putting the values in equation (1),
Therefore, pH of solution is 5.45.
(d) Ratio of concentration of potassium acetate and acetic acid is 1:1 thus,
Also,
Putting the values in equation (1),
Therefore, pH of solution is 4.76.
(e) Ratio of concentration of potassium acetate and acetic acid is 1:10 thus,
Also,
Putting the values in equation (1),
Therefore, pH of solution is 3.76.