Question

assume in a different experiment, you prepare a mixture containing 10.0 M FeSCN2+, 1.0 M H+, 0.1 MFe3+ and 0.1 M HSCN. Is the initial mixture at equilibrium? If not, in what direction must the reactionproceed to reach equilibrium? (Hint: You will need to use the value of Kc you determined in the lab

Answer 1

Answer:

The mixture is not in equilibrium, the reaction will shift to the left.

Explanation:

Based on the equilibrium:

Fe³⁺+ HSCN ⇄ FeSCN²⁺ + H⁺

kc = 30 = [FeSCN²⁺] [H⁺] / [Fe³⁺] [HSCN]

Where [] are concentrations at equilibrium. The reaction is in equilibrium when  the ratio of concentrations = kc

Q is the same expression than kc but with [] that are not in equilibrium

Replacing:

Q = [10.0M] [1.0M] / [0.1M] [0.1M]

Q = 1000

As Q > kc, the reaction will shift to the left in order to produce Fe³⁺ and HSCN untill Q = Kc