Question

n₂ + 3h₂ ⇌ 2nh₃
if more nh₃ is added, which direction will the equilibrium shift to reestablish the balance?
the equilibrium will shift to the right, forming more nh₃.
the equilibrium will shift randomly without a predictable direction.
the equilibrium will remain unchanged.
the equilibrium will shift to the left, forming more n₂ and h₂.

Explanation:

To solve this, we use Le Chatelier's Principle, which states that if a stress is applied to a system at equilibrium, the system will shift in a direction to counteract that stress. Here, adding more $\ce{NH3}$ (a product) increases the concentration of products. To counteract this, the system will shift to the left (towards the reactants) to consume the excess $\ce{NH3}$, forming more $\ce{N2}$ and $\ce{H2}$.

• The first option is incorrect because shifting right would produce more $\ce{NH3}$, which is not what's needed to counteract the excess $\ce{NH3}$.
• The second option is incorrect as equilibrium shifts are predictable based on Le Chatelier's Principle.
• The third option is incorrect because adding a substance (changing concentration) will disturb the equilibrium, so it won't remain unchanged.
• The fourth option is correct as the system shifts left to reduce the excess $\ce{NH3}$ by converting it back to $\ce{N2}$ and $\ce{H2}$.

Answer:

The equilibrium will shift to the left, forming more $\ce{N2}$ and $\ce{H2}$.