Question

In the reaction \( \mathrm{N_2(g)} + 3\mathrm{H_2(g)} \leftrightarrow 2\mathrm{NH_3(g)} \), if the equilibrium constant \( K_c = 4 \times 10^{-3} \) at a certain temperature, which of the following is true about the reaction at equilibrium?

• A. Reactants are favored over products
• B. Products are favored over reactants
• C. Reactants and products are equally favored
• D. Reaction does not reach equilibrium

Hint:

Small \( K_c \) means reaction favors reactants at equilibrium.

Answer 1

The Correct Option is A

The reaction is \(\mathrm{N_2(g)} + 3\mathrm{H_2(g)} \leftrightarrow 2\mathrm{NH_3(g)}\). The equilibrium constant \(K_c\) is \(4 \times 10^{-3}\) at a specific temperature. To determine the favored species at equilibrium, we analyze the \(K_c\) value.

Analysis:

1. The equilibrium constant expression is \(K_c = \frac{[\mathrm{NH_3}]^2}{[\mathrm{N_2}][\mathrm{H_2}]^3}\), where square brackets denote molar concentrations.
2. If \(K_c \ll 1\), reactant concentrations are higher than product concentrations at equilibrium. If \(K_c \gg 1\), product concentrations are higher.
3. Here, \(K_c = 4 \times 10^{-3}\) is much less than 1. This indicates the equilibrium lies towards the reactants, favoring them over products.

Conclusion:

Reactants are favored over products. The low \(K_c\) value signifies higher reactant concentrations than product concentrations at equilibrium.