Calculate the pH of a 0.10 M solution of sodium acetate. K_a(CH3COOH) = 1.8x10^-5 at 298 K. Use pH = 7 + tfrac12(pK_a + log c).

JEE Main levelSingle correct optionDifficulty 2 of 3ia005

Calculate the pH of a 0.10 M solution of sodium acetate. $K_{a} (CH X_{3} COOH) = 1.8 \times 1 0^{- 5}$ at 298 K. Use $pH = 7 + \frac{1}{2} (p K_{a} + lo g c)$ .

Acetate is a weak base with

K_{h} = K_{w} / K_{a} = 5.56 e - 10

[OH X^{-}] = K_{h} c

, so

pOH = \frac{1}{2} (p K_{b} - lo g c)

and

pH = 7 + \frac{1}{2} (p K_{a} + lo g c) = 7 + \frac{1}{2} (4.745 - 1) = 8.87