Question

A buffer solution contains 0.500 mole per liter each of acetic acid and sodium acetate. Determine the pH of the solution. The Ka of the acetic acid is 1.74 x 10-5. (Need an in-depth explanation with formulas please)

Answer 1

Answer:

The pH of the solution is 4.76

Explanation:

The concentration of the acetic acid and sodium acetate are 0.500 mole per liter each

The Kₐ of the acetic acid is 1.74 × 10⁻⁵

The concentration of the acetic acid CH₃COOH = 0.500 mole per liter = 0.5 M

The concentration of the sodium acetate (conjugate base) = NaCH₃COO = 0.500 mole per liter = 0.5 M

The dissociation constant, Kₐ, is given by the relation;

$K_a = \dfrac{[H_3O^+][CH_3COO^-]}{[CH_3COOH]}$

Therefore, we have;

Kₐ × [CH₃COOH]/[CH₃COO⁻] = [H₃O⁺]

1.74×10⁻⁵×0.5/0.5 = 1.74 × 10⁻⁵

Therefore, [H₃O⁺] = 1.74 × 10⁻⁵

pH = -㏒₁₀(1.74×10⁻⁵) = 4.76

The pH of the solution = 4.76.