A reaction has a two steps mechanism with the following equilibrium constant:

K₁= $\frac{[{HO}^{-}] [{HCO}_{3}^{-}]}{[{CO}_{3}^{2 -}]}$ and K₂ = $\frac{[{HCO}_{3}^{-}]}{[{HO}^{-}] [H_{2} {CO}_{3}]}$
Write the equilibrium constant expression and the chemical equation of the overall reaction.

Question

A reaction has a two steps mechanism with the following equilibrium constant:

K₁=

\frac{[{HO}^{-}] [{HCO}_{3}^{-}]}{[{CO}_{3}^{2 -}]}

and K₂ =

\frac{[{HCO}_{3}^{-}]}{[{HO}^{-}] [H_{2} {CO}_{3}]}

Write the equilibrium constant expression and the chemical equation of the overall reaction.

| General Chemistry 3

Accepted Answer

K_overall = K₁ x K₂

K_overall =

\frac{[{HO}^{-}] [{HCO}_{3}^{-}]}{[{CO}_{3}^{2 -}]}

x

\frac{[{HCO}_{3}^{-}]}{[{HO}^{-}] [H_{2} {CO}_{3}]}

K_overall =

\frac{{[{HCO}_{3}^{-}]}^{2}}{[{CO}_{3}^{2 -}] [H_{2} {CO}_{3}]}

2 HCO₃^-(g)

⇄

CO₃^2-(g) + H₂CO₃(g)

Exercise 3 | Chemical Equilibrium