COMEDK · Chemistry · 23. d and f Block Elements

Identify the incorrect statement.

A \(\mathrm{Cr}^{2+}\) acts as reducing agent while \(\mathrm{Mn}^{3+}\) acts as an oxidising agent though both the ions have \(\mathrm{d}^4\) configuration.
B The second and third ionisation enthalpies of Mn and Fe, respectively, have lower values than expected.
C Transition metals readily form alloys because their metallic radii are within about \(15 \%\) of each other.
D Ability of Fluorine to stabilise higher oxidation states in transition metals is due to the low lattice enthalpy of the fluorides.

Verified Solution

Answer & Solution

Correct Answer

(D) Ability of Fluorine to stabilise higher oxidation states in transition metals is due to the low lattice enthalpy of the fluorides.

Step-by-step Solution

Detailed explanation

(1) \(Cr^{2+}\) \((3d^4)\) gets oxidised to \(Cr^{3+}\) \((3d^3)\), which has a stable \(t_{2g}^3\) configuration, so it acts as a reducing agent. \(Mn^{3+}\) \((3d^4)\) gets reduced to \(Mn^{2+}\) \((3d^5)\), which has a stable half-filled configuration, so it acts as an…

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Explore more questions on app

From COMEDK

Explore more questions on app