H2S(aq)⇌HS−(aq)+H+(aq), K1 = 9.06×10−8, and HS−(aq)⇌S2−(aq)+H+(aq), K2 = 1.18×10−19, what is the equilibrium constant Kfinal for the following reaction? S2−(aq)+2H+(aq)⇌H2S(aq)

Respuesta :

Answer:

Therefore the equilibrium constant  [tex]K_{final}[/tex] is 9.35× 10²⁵

Explanation:

Equilibrium constant:

Equilibrium constant is used to find out the ratio of the concentration of the product to that of reactant.

xA+yB→zC

The equilibrium constant K,

[tex]k=\frac{[C]^z}{[A]^x[B]^y}[/tex]

Here [A] is equilibrium concentration of A

[B] is equilibrium concentration of B

[C] is equilibrium concentration of C.

1.  [tex]H_2S(aq)\rightleftharpoons HS^-(aq)+H^+(aq)[/tex]          [tex]K_1= 9.06 \times 10^{-8}[/tex]

[tex]K_1=\frac{[HS^-][H^+]}{[H_2S]}[/tex]

2.   [tex]HS^-(aq)\rightleftharpoons S^{2-}(aq)+H^+(aq)[/tex]      [tex]K_2= 1.18 \times 10^{-19}[/tex]

[tex]K_2=\frac{[S^{2-}][H^+]}{[HS^-]}[/tex]

3.

[tex]S^{2-}(aq)+2H^+(aq)\rightleftharpoons H_2S(aq)[/tex]

[tex]K_3=\frac{[H_2S]}{[S^{2-}][H^+]^2}[/tex]

Therefore,

[tex]k_1k_2=\frac{[HS^-][H^+]}{[H_2S]}\frac{[S^{2-}][H^+]}{[HS^-]}[/tex]

[tex]\Rightarrow k_1k_2=\frac{[S^{2-}][H^+]^2}{[H_2S]}[/tex]

[tex]\Rightarrow k_1k_2=\frac{1}{K_3}[/tex]

[tex]\Rightarrow K_3=\frac{1}{K_1K_2}[/tex]

[tex]\Rightarrow K_3=\frac{1}{9.06\times 10^{-8}\times 1.18\times 10^{-19}}[/tex]

⇒K₃=9.35× 10²⁵

[tex]K_3=K_{final}[/tex]          

Therefore the equilibrium constant  [tex]K_{final}[/tex] is 9.35× 10²⁵