The equilibrium constant for the dissociation of acetic acid at 25oC is 1.85x10-5. What will be the equilibrium concentration of H+ at 25oC, if the initial concentration of acetic acid was 0.100 M? CH3COOH (aq) ↔ CH3COO- (aq) + H+ (aq) Give your answer to two significant figures and in decimal form.

Respuesta :

Answer:

Equilibrium concentration of [tex]H^{+}[/tex] is [tex]1.4\times 10^{-3}M[/tex]

Explanation:

Construct an ICE table to calculate changes in concentration at equilibrium.

   [tex]CH_{3}COOH\rightleftharpoons CH_{3}COO^{-}+H^{+}[/tex]

I:     0.1                                                          0                     0

C:     -x                                                          +x                   +x

E:    0.1-x                                                       x                      x

[tex]\frac{[CH_{3}COO^{-}][H^{+}]}{[CH_{3}COOH]}[/tex]= [tex]K_{a}(CH_{3}COOH)[/tex]

(species inside third bracket represent equilibrium concentrations)

[tex]\frac{x^{2}}{0.1-x}=1.85\times 10^{-5}[/tex]

or, [tex]x^{2}+(1.85\times 10^{-5})x-(1.85\times 10^{-6})=0[/tex]

So, [tex]x=\frac{-(1.85\times 10^{-5})+\sqrt{(1.85\times 10^{-5})^{2}+(4\times 1.85\times 10^{-6})}}{2}[/tex]M

or, [tex]x=1.4\times 10^{-3}M[/tex]

So, equilibrium concentration of [tex]H^{+}[/tex]=[tex][H^{+}][/tex]=x=[tex]1.4\times 10^{-3}M[/tex]

The equilibrium concentration will be  [tex]H^{+} =1.4\times10^{-3}[/tex]

What will be the equilibrium concentration?

ICE table for the calculation of changes in concentration at equilibrium.

[tex]CH_{3} COOH= CH_{3}COO^{-1} +H^{+}[/tex]

 

I:     0.1                                                          0                     0

C:     -x                                                          +x                   +x

E:    0.1-x                                                       x                      x

[tex]\dfrac{(CH_{3} COO^{-1} ) (H^{+} )}{(CH_{3} COOH)} } =K_{a} \times (CH_{3} COOH)[/tex]

species inside the third bracket represent equilibrium concentrations

[tex]\dfrac{x^{2} }{0.1-x} = 1.85\times10^{-5}[/tex]

[tex]x^{2} +(1.85\times10^{-5} )\times x-(1.85\times10^{-5} )=0[/tex]

[tex]\dfrac{-(1.85\times10^{-5} )+\sqrt{(1.85\times10^{-5})^{2} +(4\times1.85\times10^{-5} ) } }{2}[/tex]

[tex]x=1.4\times10^{-3}[/tex]

The equilibrium concentration will be  [tex]H^{+} =1.4\times10^{-3}[/tex]

To know more about Equilibrium Concentration follow

https://brainly.com/question/13414142

ACCESS MORE
EDU ACCESS