Consider the chemical equilibrium of the reaction:
[tex]$NH_4 OH(aq) \Leftrightarrow NH_4^{+}(aq)+OH^{-}(aq)$[/tex]
What will happen to the chemical equilibrium if [tex]$NH _4 Cl$[/tex] is added to this solution?
A. The chemical equilibrium will shift to the right.
B. The chemical equilibrium will not shift.
C. The chemical equilibrium will shift to the left.
Answer (2)
Adding N H 4 Cl increases the concentration of N H 4 + ions.
According to Le Chatelier's principle, the equilibrium shifts to relieve the stress.
The equilibrium shifts to the left to counteract the increase in N H 4 + concentration.
Therefore, the chemical equilibrium shifts to the left. T h ec h e mi c a l e q u i l ib r i u m w i ll s hi f tt o t h e l e f t .
Explanation
Understanding the Problem We are given the chemical equilibrium reaction: N H 4 O H ( a q ) ⇔ N H 4 + ( a q ) + O H − ( a q ) . We need to determine what happens to the equilibrium when N H 4 Cl is added to the solution.
Effect of Adding Ammonium Chloride N H 4 Cl is a strong electrolyte, meaning it dissociates completely in water: N H 4 Cl ( a q ) → N H 4 + ( a q ) + C l − ( a q ) . Therefore, adding N H 4 Cl to the solution increases the concentration of N H 4 + ions.
Applying Le Chatelier's Principle According to Le Chatelier's principle, if a change of condition (like adding a product) is applied to a system in equilibrium, the equilibrium will shift in a direction that relieves the stress. In this case, the stress is the increase in N H 4 + concentration. To relieve this stress, the equilibrium will shift to the left, favoring the reverse reaction to consume the excess N H 4 + and O H − ions and form more N H 4 O H .
Conclusion Therefore, the chemical equilibrium will shift to the left.
Examples
Consider a scenario where you're brewing tea, and you find it's too acidic. Adding a bit of baking soda (a base) can help neutralize the acidity, shifting the equilibrium of the tea's chemical components to a more balanced state. Similarly, in environmental science, understanding Le Chatelier's principle helps predict how adding pollutants to a lake might affect the delicate balance of aquatic life. By knowing how chemical equilibria respond to disturbances, we can better manage and mitigate the impacts of human activities on natural systems.
When N H 4 Cl is added to the solution, it increases the concentration of N H 4 + ions. According to Le Chatelier's principle, this increase causes the equilibrium to shift left. The chosen answer is C: The chemical equilibrium will shift to the left.
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