(i) Transition metals easily form alloys with other transition metals because they have almost similar size. So they can easily replace each other in the crystal lattice.
(ii) The transition metal oxides in the lower oxidation state of metals are basic in nature and in higher oxidation state they are acidic in nature. The oxidation state of Mn in Mn2O3 is +3 and Mn2O7 has +7. Therefore, Mn2O3 is basic and Mn2O7 is acidic.
(iii) The common oxidation state of lanthanide metals is +3.Eu2+ is formed by losing the two s electrons, acquires half filled (4f7) configuration. But still, they oxidize to their common +3 state. So, the Eu2+ loses one electron and is oxidized to Eu3+. So Eu2+ acts as a strong reducing agent.