What is the equilibrium expression for the reaction 2H₂(g) + O₂(g) ⇌ 2H₂O(g)?

In chemical equilibrium, the equilibrium constant expression is written based on the concentrations of the products raised to the power of their coefficients, divided by the concentrations of the reactants raised to the power of their coefficients.

For the reaction 2H₂(g) + O₂(g) ⇌ 2H₂O(g), the products are 2H₂O and the reactants are 2H₂ and O₂. The correct equilibrium expression can be derived as follows:

1. Identify the products and their coefficients:

• H₂O has a coefficient of 2.

2. Identify the reactants and their coefficients:

• H₂ has a coefficient of 2.

• O₂ has a coefficient of 1.

Putting this together, the equilibrium constant (Kc) expression is formed by taking the concentration of the products over the concentration of the reactants:

Kc = [H₂O]² / ([H₂]²[O₂])

This correctly reflects the stoichiometry of the balanced equation. Thus, the option that represents this expression accurately is indeed the choice that states Kc = [H₂O]² / ([H₂]²[O₂]).

The other choices either mis