Answer:
The correct option is C
Explanation:
From the question we are told that
The concentration of the acid solution is [tex]C = 2.5M[/tex]
The pH of the acid is [tex]pH_a = 2.5[/tex]
Looking at the pH of the acid we can say that it is a strong acid
This because its pH fall between 0-7
The generally dissociation chemical equation for this acid is represented as
[tex]HA[/tex] ⇄ [tex]H^{+} + A^{-}[/tex]
So the equilibrium constant for this reaction is mathematically represented as
[tex]K_c = \frac{[H^+] [A^-]}{[HA]}[/tex]
and the pH of can be mathematically represented as
[tex]pH = -log [H^+][/tex]
=> [tex]H^+ = 10^{-pH}[/tex]
substituting value
[tex]H^+ = 10^{-(2.50)}[/tex]
[tex]H^+ = 0.0031623M[/tex]
Looking at the chemical equation we see that the ratio of the moles for the product is one is to one
Secondly the new concentration of the reactant will be
[tex]HA = 2.5 - 00031623[/tex]
[tex][A^-] = 0.003163 M[/tex]
So the equilibrium constant is
[tex]K_c = \frac{0.0031623 * 0.0031623 }{(2.5 - 0.0031623 }[/tex]
[tex]K_c = 4* 10^{-6}[/tex]
