Answer: The percent ionization of HA is 0.13 %
Explanation:
We are given:
Molarity of HA solution = 0.10 M
The chemical equation for the ionization of HA follows:
[tex]HA\rightarrow H^++A^-[/tex]
Initial: 0.1
At eqllm: (0.1-x) x x
The expression of [tex]K_a[/tex] for above equation follows:
[tex]K_a=\frac{[H^+][A^-]}{[HA]}[/tex]
We are given:
[tex]K_a=1.8\times 10^{-7}[/tex]
Putting values in above equation, we get:
[tex]1.8\times 10^{-7}=\frac{x\times x}{0.1-x}\\\\x^2+(1.8\times 10^{-7})x-1.8\times 10^{-8}=0\\\\x=0.00013,-0.00013[/tex]
Neglecting the negative value of 'x' because concentration cannot be negative.
To calculate the percent ionization, we use the equation:
[tex]\%\text{ ionization}=\frac{[H^+]_{eq}}{[HA]_i}\times 100[/tex]
[tex][H^+]_{eq}=x=0.00013M[/tex]
[tex][HA]_i=0.1M[/tex]
Putting values in above equation, we get:
[tex]\%\text{ ionization}=\frac{0.00013}{0.1}\times 100\\\\\%\text{ ionization}=0.13\%[/tex]
Hence, the percent ionization of HA is 0.13 %