IDNLearn.com is your trusted platform for finding reliable answers. Join our community to receive prompt and reliable responses to your questions from experienced professionals.
Answer:
"7.46" is the correct answer.
Explanation:
Given that:
[tex]pH=4.64[/tex]
[tex]C=0.015 \ M[/tex]
The equation:
⇒ [tex]HA \rightleftharpoons H^++A^-[/tex]
HA = C - Cα
H⁺ = Cα
A⁻ = Cα
now,
⇒ [tex]pH=-log(H^+)[/tex]
[tex]=-log(C \alpha)[/tex]
[tex]=4.64[/tex]
[tex]C \alpha = 2.3\times 10^-5 \ M[/tex]
As we know,
⇒ [tex]K_a=C \alpha^2[/tex]
[tex]=(\frac{C \alpha}{C} )^2\times C[/tex]
[tex]=\frac{(2.3\times 10^{-5})^2}{0.015}[/tex]
[tex]=3.5\times 10^{-8}[/tex]
hence,
⇒ [tex]pK_a=-log(K_a)[/tex]
[tex]=7.46[/tex]