Question

Statement-I $[\text{Co}(\text{C}_2\text{O}_4)_3]^{3-}$ has magnetic moment of $4.9 \text{ BM}$ & hybridization is $sp^3d^2$. Statement-II $[\text{Ni}(\text{CN})_4]^{2-}, [\text{Cr}(\text{H}_2\text{O})_6]^{2+}$ and $[\text{MnF}_6]^{4-}$ have square planar, octahedral and octahedral geometry respectively and $dsp^2, sp^3d^2, d^2sp^3$ hybridization respectively and $\mu=0, 4.9 \text{ BM}, 5.9 \text{ BM}$ respectively.

• A. Both statements are correct
• B. Statement-I is correct & statement-II is incorrect
• C. Statement-I is incorrect & statement-II is correct
• D. Both statements are incorrect.

Hint:

In CFT/VBT questions, verify oxidation state, ligand field strength, and the resulting hybridization and magnetic moment ($\mu = \sqrt{n(n+2)} \text{ BM}$).

Answer 1

The Correct Option is D

Statement I: $[\text{Co}(\text{C}_2\text{O}_4)_3]^{3-}$. $\text{Co}^{3+}$ ($d^6$). Oxalate is $\text{SF}$. Low spin $d^2sp^3$. $\mu=0$. (I is Incorrect).
Statement II: Hybridization of $[\text{MnF}_6]^{4-}$ ($\text{Mn}^{2+}, d^5, \text{WF}$) is $sp^3d^2$. Statement claims $d^2sp^3$. (II is Incorrect).
Since both statements contain definitive errors, both are incorrect.