Solution of task 319 of Chemistry Book Shimanovich 2003

Solution of task 319 of Chemistry Book Shimanovich 2003

319. What are the complex compounds called double salts? Write the dissociation equations for K4 [Fe (CN) 6] and (NH4) 2Fe (SO4) 2 salts in an aqueous solution.
In what case does precipitation of iron (II) hydroxide precipitate, if alkaline solution is added to each of them? Write the molecular and ion-molecular equation of the reaction.