The correct statement about iron includes<br>(I) the highest oxidation state of iron is +6 in K2FeO4 — d and f Block Elements Chemistry Question
Question
The correct statement about iron includes<br>(I) the highest oxidation state of iron is +6 in K2FeO4<br>(II) that the iron shows +2 oxidation state with six electrons in the 3d orbitals<br>(III) the common oxidation state of iron is +3 with five unpaired electrons in the 3d orbital
💡 Solution & Explanation
Step 1: Passivity of a metal refers to the loss of its chemical reactivity due to the formation of a thin, non-reactive, protective oxide layer on its surface. Step 2: Concentrated nitric acid (conc. HNO3) is a powerful oxidizing agent that reacts with iron to form a highly protective, impermeable layer of iron oxide (mainly Fe3O4), which prevents further reaction. Step 3: Thus, iron is made passive by concentrated nitric acid, corresponding to option (c).