Question: is fe soluble or insoluble?
Answer: Hydroxide salts of Group II elements (Ca, Sr, and Ba) are slightly soluble. Hydroxide salts of transition metals and Al3+ are insoluble. Thus, Fe(OH)3, Al(OH)3, Co(OH)2 are not soluble. Most sulfides of transition metals are highly insoluble, including CdS, FeS, ZnS, and Ag2S.