Find the pH of a solution formed by mixing equal volume of solution of 0.1 M sodium propionate and 0.1 molar propionic acid. (Given The dissociation constant of propionic acid is 1.3 10⁻⁵ )

Step-by-step solution

The mixture of propionic acid and sodium propionate forms an acidic buffer. Using the Henderson-Hasselbalch equation: pH = p K_a + ( [ Salt ] [ Acid ] ) Since equal volumes of 0.1 M solutions are mixed, the concentrations of the salt and the acid in the final mixture are equal. pH = p K_a + (1) pH = p K_a = - (K_a) pH = - (1.3 10⁻⁵) pH = 5 - (1.3) pH = 5 - 0.1139 = 4.8861 4.89