Consider the insoluble compound iron(II) sulfide, FeS. The iron (II) ion also forms a complex with cyanide ions. Write a balanced net ionic equation to show why the solubility of FeS (s) increases in the presence of cyanide ions and calculate the equilibrium constant for this reaction. For Fe(CN), K-7.7 10. Use the pull-down boxes to specify states such as (aq) or (s).