Silver ions can be reduced by
iron(II) ions in the following net ionic equation. Fe2+ aqueous plus Ag+ aqueous are
in equilibrium with Fe3+ aqueous plus Ag solid. What is the correct equation for 𝐾
𝑐 for this reaction?
𝐾 𝑐 is the equilibrium
constant. An equilibrium constant is a value
that expresses the relationship between reactant and product concentrations at
equilibrium. Let’s consider this generic
equilibrium reaction equation.
In this equation, the lowercase
letters represent molar coefficients and the uppercase letters represent chemical
formulas. The equation for the equilibrium
constant for this reaction would be 𝐾 𝑐 equals the concentration of the products
raised to their molar coefficients divided by the concentration of the reactants
raised to their molar coefficients.
It’s important to note that species
in the solid phase and pure water when used as a solvent are not included in the
equilibrium constant equation. We can apply all of this
information to the reaction given in the question. We can see that silver is a solid
in this chemical reaction. So it won’t be included in the
equilibrium constant equation. Following the generic equation for
an equilibrium constant, we can write the equilibrium constant equation for this
reaction, omitting silver because it is a solid.
In conclusion, the correct
equilibrium constant equation for the given reaction is 𝐾 𝑐 equals the
concentration of Fe3+ divided by the concentration of Fe2+ times the concentration