Answer:
The value of the [tex]K_a[/tex] of the acid is :
[tex]K_a=4.109\times 10^{-8}[/tex]
Explanation:
The pH of the weak acid solution = 3.879
Concentration of hydrogen ions = [tex][H^+][/tex]
[tex]pH=-\log[H^+][/tex]
[tex]3.879=-\log[H^+][/tex]
[tex][H^+]=10^{-3.876}=0.0001321 M[/tex]
Concentration of hypochlorous acid solution = [HClO]= 0.426 M
[tex]HClO(aq)\rightarrow H^+(aq)+ClO^-(aq)[/tex]
Initially:
0.426 M 0 0
At equilibrium
(0.426-0.0001321)M 0.0001321 M 0.0001321 M
The expression of [tex]K_a[/tex] will be given as;
[tex]K_a=\frac{[H^+][ClO^-]}{[HClO]}[/tex]
[tex]K_a=\frac{0.0001321 M\times 0.0001321 M}{(0.426-0.0001321) M}[/tex]
[tex]K_a=4.109\times 10^{-8}[/tex]
The value of the [tex]K_a[/tex] of the acid is :
[tex]K_a=4.109\times 10^{-8}[/tex]