Answer:
Ka = 0.16
Explanation:
HClO₄ is a strong acid and it will dissociate completely to give hydrogen ion and the conjugate base.
The pH of HClO₄ will be calculated as:
pH = -log[H⁺]
pH = -log[0.04] = 1.4
The trichloroacetic acid is a weak acid and it will not dissociate completely.
The dissociation will be:
[tex]CCl_{3}COOH---> CCl_{3}COO^{-} + H^{+}[/tex]
Initial 0.05 0 0
Change -x +x +x
Equilibrium 0.05-x x x
Ka = [tex]\frac{[H^{+}][ClO_{4}^{-}]}{[HClO_{4}]}[/tex]
As pH of the acid = 1.4 it means the concentration of hydrogen ion is 0.04.
Therefore
x = 0.04
Putting values
Ka = [tex]\frac{(0.04)(0.04)}{0.05-0.04}=0.16[/tex]
