NEETChemistryCoordination Compounds
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): For the complex [ Fe ( CN )₆]⁴⁻ , the crystal field splitting energy ( _o ) is greater than the pairing energy ( P ), while for [ Fe ( H ₂ O )₆]²⁺ , _o Reason (R): [ Fe ( CN )₆]⁴⁻ is a low spin complex whereas [ Fe ( H ₂ O )₆]²⁺ is a high spin complex. In the light of the above statements, choose t
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
Step-by-step solution
In [ Fe ( CN )₆]⁴⁻ , the central metal ion is Fe ²⁺ . Since CN ^- is a strong field ligand, it causes a large crystal field splitting, making _o > P . This leads to the pairing of electrons in the t_ 2g orbitals, resulting in a low spin complex. In [ Fe ( H ₂ O )₆]²⁺ , H ₂ O is a weak field ligand, causing a smaller crystal field splitting, making _o Thus, both Assertion (A) and Reason (R) are correct statements. However, the spin state of the complex is a consequence of the relative magnitude of _o and P , not the