Answer: [tex]K_a[/tex] for the acid is [tex]5.75\times 10^{-5} [/tex]
Explanation:
[tex]C_6H_5COOH\rightarrow H^+C_6H_5COO^-[/tex]
cM 0 0
[tex]c-c\alpha[/tex] [tex]c\alpha[/tex]
So dissociation constant will be:
[tex]K_a=\frac{(c\alpha)^{2}}{c-c\alpha}[/tex]
Give c= 0.341 M and = 2.351
[tex]K_a=?[/tex]
[tex]pH=-log[H^+][/tex]
[tex][H^+]=10^{-2.351}=0.0044[/tex]
[tex][H^]=c\alpha=0.0044[/tex]
[tex]K_a=\frac{(0.0044)^{2}}{0.341-0.0044}[/tex]
[tex]K_a=5.75\times 10^{-5} [/tex]
Thus [tex]K_a[/tex] for the acid is [tex]5.75\times 10^{-5} [/tex]
