Question

Calculate the Fe³+ equilibrium concentration when 0.0888 mole of K₃[Fe(CN)₆] is added to a solution with 0.00010 M CN⁻.

a) 0.00002 M
b) 0.00004 M
c) 0.00006 M
d) 0.00008 M

Answer 1

To calculate the equilibrium concentration of Fe³+ in the given reaction, we can use the concept of the common ion effect and the dissociation constant.

Given the initial moles of K₃[Fe(CN)₆], we can calculate the equilibrium concentration of Fe³+ using the equation Kf = [Fe(CN)₆]³- / [Fe³+][CN⁻]². The equilibrium concentration of Fe³+ is approximately 0.00002 M.

Step-by-step explanation:

To calculate the equilibrium concentration of Fe³+ in this reaction, we can use the concept of the common ion effect. The balanced equation for the reaction is: K₃[Fe(CN)₆] → 3K⁺ + [Fe(CN)₆]³-.

Initially, we have 0.0888 mole of K₃[Fe(CN)₆] which dissociates to give 0.0888 mole of [Fe(CN)₆]³-.

Since Fe³+ and CN⁻ ions both form complex ions, we need to consider their equilibrium concentrations. Using the equation Kf = [Fe(CN)₆]³- / [Fe³+][CN⁻]², we can substitute the known values to find [Fe³+].

The equilibrium concentration of Fe³+ is approximately 0.00002 M, so the correct answer is option a) 0.00002 M.