The equilibrium constants for the two reactions are known:
M ^m++ 4 L^- ⇄ [ML4]^m^-⁴ $\quad$ K_f
HL ⇄ H⁺ +L^- $\quad$ K_a
What is the equilibrium constant, K_overall, for the reaction, M ^m++ 4 HL ⇄ [ML4 ]^m ⁺ ⁴ +4H⁺?

Question

The equilibrium constants for the two reactions are known:
M ^m++ 4 L^- ⇄ [ML4]^m^-⁴

\quad

K_f
HL ⇄ H⁺ +L^-

\quad

K_a
What is the equilibrium constant, K_overall, for the reaction, M ^m++ 4 HL ⇄ [ML4 ]^m ⁺ ⁴ +4H⁺?

Quizplus · Accepted Answer

The overall equilibrium constant for a reaction obtained by combining other reactions is the product of the equilibrium constants for those reactions. Since the second reaction involves 4 HL, its equilibrium constant is raised to the power of 4 when calculating the overall equilibrium constant.

The Equilibrium Constants for the Two Reactions Are Known \quad Kf HL ⇄ H+ +L-

The Equilibrium Constants for the Two Reactions Are Known $\quad$ K_f
HL ⇄ H⁺ +L^-