JEE MainChemistryd and f Block Elements
Which of the following statements regarding the oxoanions of transition metals is correct?
Options
- AThe manganate ion ( MnO ₄²⁻ ) is diamagnetic, while the permanganate ion ( MnO ₄⁻ ) is paramagnetic.
- BBoth the chromate ion ( CrO ₄²⁻ ) and the permanganate ion ( MnO ₄⁻ ) are diamagnetic and involve p -d bonding
- CIn the dichromate ion ( Cr ₂ O ₇²⁻ ), all the Cr-O bonds are of equal length.
- DThe conversion of chromate to dichromate in an acidic medium is a redox process that increases the oxidation s
Correct answer
B. Both the chromate ion ( CrO ₄²⁻ ) and the permanganate ion ( MnO ₄⁻ ) are diamagnetic and involve p -d bonding
Step-by-step solution
Let us evaluate each statement: Statement 1 is incorrect. The manganate ion ( MnO ₄²⁻ ) contains Mn in the +6 oxidation state ( d^1 configuration), making it paramagnetic. The permanganate ion ( MnO ₄⁻ ) contains Mn in the +7 oxidation state ( d^0 configuration), making it diamagnetic. Statement 2 is correct. In CrO ₄²⁻ , Cr is in the +6 oxidation state ( d^0 ), and in MnO ₄⁻ , Mn is in the +7 oxidation state ( d^0 ). Both are diamagnetic. The -bonding in these oxoanions occurs via the overlap of oxygen p -orbitals