Answer:
ka = 1.9 × 10^-11
Explanation:
For a weak acid / conjugate base
and
conjugate base / weak acid
[tex]k_a \times k_b = k_w[/tex]
where
kw is the dissociation constant of water
= 10⁻⁴
kb = 5.4 × 10⁻⁴
[tex]k_a = \frac{k_w}{k_b}[/tex]
[tex]k_a = \frac{10^-^4}{ 5.4 \times 10^-^4} \\\\k_a = 1.9 \times 10^-^1^1[/tex]
[tex]k_a = \frac{[conjugate base][H^+]}{Acid}[/tex]
[tex]k_b = \frac{[Acid][OH^-]}{cojugate base}[/tex]
[tex]k_w = \frac{[conjugate base][H^+]}{Acid} \times \frac{[Acid][OH^-]}{cojugate base}[/tex]
[tex]k_w = [H^+] [OH^-]\\k_w = K_a \times k_b[/tex]
