Answer:
The pH is equal to 4.41
Explanation:
Since HClO is a weak acid, its dissociation in aqueous medium is:
HClO ⇄ ClO- + H+
start: 0.05 0 0
change -x +x +x
balance 0.05-x x x
As it is a weak acid it dissociates very little, in its ClO- and H + ions, so the change is negative, where x is a degree of dissociation.
the acidity constant when equilibrium is reached is equal to:
[tex]Ka=\frac{[ClO-]*[H+]}{[HClO]}=\frac{x*x}{0.05-x}=3x10^{-8}[/tex]
The 0.05-x fraction can be approximated to 0.05, because the ionized fraction (x) is very small, therefore we have:
[tex]3x10^{-8}=\frac{x^{2} }{0.05}[/tex]
clearing the x and calculating its value we have:
[tex]x=3.87x10^{-5}=[H+]=[ClO-][/tex]
the pH can be calculated by:
[tex]pH=-log[H+]=-log[3.87x10^{-5}]=4.41[/tex]
