What is the correct expression for the formation constant (Kf ) for the complex ion Fe(CN) 6^3-
Fe3+ + 6 CN- <----------> [Fe(CN)6]3-, 1.0 x 10^31.
Kf = [Fe(CN)6]3-/[Fe^3+][CN^-]^6
The correct expression for the formation constant (Kf) of the complex ion Fe(CN)6^3- can be determined by writing the chemical equation for the formation reaction. The formation reaction can be written as:
Fe^3+ + 6CN^- -> Fe(CN)6^3-
The expression for the formation constant (Kf) is given by the following equation:
Kf = [Fe(CN)6^3-] / [Fe^3+][CN^-]^6
In this expression, [Fe(CN)6^3-], [Fe^3+], and [CN^-] represent the equilibrium concentrations of the complex ion, Fe^3+ ion, and CN^- ion, respectively. The exponent 6 is used since there are 6 CN^- ions involved in the reaction.
The formation constant for the complex ion Fe(CN)₆³⁻, denoted as Kf, represents the equilibrium constant for the formation of the complex ion from its constituent ions.
To determine the correct expression for Kf, we should consider the balanced chemical equation that describes the formation of Fe(CN)₆³⁻. The formation of Fe(CN)₆³⁻ can be represented as follows:
Fe³⁺ + 6 CN⁻ → Fe(CN)₆³⁻
The concentration of each species participating in the reaction equation is denoted as [ ]. Therefore, we can express the expression for Kf as:
Kf = [Fe(CN)₆³⁻] / ([Fe³⁺] * [CN⁻]⁶)
In this expression, the brackets represent the concentrations of the respective species involved in the equilibrium. It's important to note that the concentration should be expressed in molarity (moles per liter, M).
By calculating the concentrations of Fe(CN)₆³⁻, Fe³⁺, and CN⁻, you can then substitute these values into the expression to determine the formation constant (Kf) for the complex ion.