The reaction Fe 3+(aq) + Cl -(aq) ⇌ FeCl 2+(aq) is endothermic. How will the equilibrium concentration of FeCl 2+ change whenCl - is precipitated by addition of AgNO3?

Verified step by step guidance

1. Identify the initial equilibrium reaction: Fe^{3+}(aq) + Cl^{-}(aq) \rightleftharpoons FeCl^{2+}(aq).
2. Recognize that the reaction is endothermic, meaning it absorbs heat.
3. Understand that adding AgNO_3 will precipitate Cl^{-} as AgCl, reducing the concentration of Cl^{-} ions in the solution.
4. Apply Le Chatelier's Principle: the system will shift to counteract the change, in this case, to increase the concentration of Cl^{-} ions.
5. Conclude that the equilibrium will shift to the left, decreasing the concentration of FeCl^{2+} ions.

Key Concepts

Le Chatelier's Principle

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change. In this case, adding AgNO3 precipitates Cl-, which reduces its concentration in the solution. According to Le Chatelier's Principle, the equilibrium will shift to the left to produce more Cl- ions, thereby affecting the concentration of FeCl2+.

Equilibrium Constant (K)

The equilibrium constant (K) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. For the reaction in question, K is determined by the concentrations of Fe3+, Cl-, and FeCl2+. Changes in concentration due to precipitation will influence the system's ability to maintain this constant, leading to shifts in the equilibrium position.

Endothermic Reactions

An endothermic reaction is one that absorbs heat from its surroundings, resulting in a decrease in temperature of the environment. In the context of the given reaction, the endothermic nature means that increasing temperature would favor the formation of products. However, since the question focuses on the effect of Cl- precipitation, the heat aspect is less relevant, but understanding the energy dynamics can help in predicting how the system responds to changes.