To determine the equilibrium constant of a reaction, we need to understand the concept of chemical equilibrium. In a chemical reaction that has reached equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction. At this point, the concentrations of the reactants and products remain constant.
The equilibrium constant, [tex]\( K_{\text{eq}} \)[/tex], is a value that expresses the relationship between the concentrations of the reactants and products at equilibrium. It is defined as the ratio of the concentrations of the products to the concentrations of the reactants, each raised to the power of their respective coefficients in the balanced chemical equation.
Given the choices:
A. [tex]\( K_{\text{eq}} = [\text{products}][\text{reactants}] \)[/tex]
B. [tex]\( K_{\text{eq}} = \frac{[\text{products}]}{[\text{reactants}]} \)[/tex]
C. [tex]\( K_{\text{eq}} = [\text{reactants}] + [\text{products}] \)[/tex]
D. [tex]\( K_{\text{eq}} = \frac{[\text{reactants}]}{[\text{products}]} \)[/tex]
Choice A suggests that the equilibrium constant is the product of the concentrations of the reactants and products, which is incorrect.
Choice C suggests that the equilibrium constant is the sum of the concentrations of the reactants and products, which is incorrect.
Choice D suggests that the equilibrium constant is the ratio of the concentration of the reactants to the concentration of the products, which is incorrect as the equilibrium constant usually has products in the numerator and reactants in the denominator.
Therefore, the correct definition aligns with Choice B: [tex]\( K_{\text{eq}} = \frac{[\text{products}]}{[\text{reactants}]} \)[/tex].
Thus, the correct equilibrium constant for the reaction is given by:
[tex]\[
K_{\text{eq}} = 2 \implies \text{Answer B: } K_{\text{eq}} = \frac{[\text{products}]}{[\text{reactants}]}
\][/tex]
