COMEDK2023Evening ShiftChemistryd and f Block ElementsActual
Identify the incorrect statement.
Options
- ACr ²⁺ acts as reducing agent while Mn ³⁺ acts as an oxidising agent though both the ions have d ^4 configurati
- BThe second and third ionisation enthalpies of Mn and Fe, respectively, have lower values than expected.
- CTransition metals readily form alloys because their metallic radii are within about 15 % of each other.
- DAbility of Fluorine to stabilise higher oxidation states in transition metals is due to the low lattice enthal
Correct answer
D. Ability of Fluorine to stabilise higher oxidation states in transition metals is due to the low lattice enthal
Step-by-step solution
(1) Cr²⁺(3d^4) gets oxidised to Cr³⁺(3d^3) , which has a stable t_ 2g ^3 configuration, so it acts as a reducing agent. Mn³⁺(3d^4) gets reduced to Mn²⁺(3d^5) , which has a stable half-filled configuration, so it acts as an oxidising agent. This statement is correct. (2) Second ionisation of Mn: 3d^54s^1 3d^5 + e^- and third ionisation of Fe: 3d^6 3d^5 + e^- both lead to a stable half-filled 3d^5 core, making these ionisation enthalpies lower than expected. This statement is correct. (3) Transition metals have metal