Equilibrium constant formula give

For a general reversible reaction:

$$a\text{A} + b\text{B} \rightleftharpoons c\text{C} + d\text{D}$$

where A, B, C, and D are chemical species, and $a, b, c, d$ are their respective stoichiometric coefficients.

The equilibrium constant in terms of molar concentrations ($K_c$) is given by:

$$K_c = \frac{[\text{C}]^c[\text{D}]^d}{[\text{A}]^a[\text{B}]^b}$$

where:

• $[\text{A}]$, $[\text{B}]$, $[\text{C}]$, and $[\text{D}]$ represent the molar concentrations of the reactants and products at equilibrium.
• The exponents $a, b, c, d$ are the stoichiometric coefficients from the balanced chemical equation.

For reactions involving gases, the equilibrium constant can also be expressed in terms of partial pressures ($K_p$):

$$K_p = \frac{(P_{\text{C}})^c(P_{\text{D}})^d}{(P_{\text{A}})^a(P_{\text{B}})^b}$$

where $P_{\text{X}}$ represents the partial pressure of gas X at equilibrium.