Question

The correct increasing order of stability of the complexes based on \( \Delta \) value is:

• A. IV < III < II < I
• B. III < II < IV < I
• C. I < II < IV < III
• D. II < III < I < IV

Hint:

To determine the stability order based on \( \Delta \), consider the ligand field splitting energy and the ligand's electron-donating or withdrawing effects.

Answer 1

The Correct Option is C

Complex stability correlates with crystal field splitting energy (\( \Delta \)). Higher \( \Delta \) values indicate greater complex stability.
The stability order based on \( \Delta \) values is presented in the following options:

1. Option 1: IV < III < II < I
2. Option 2: III < II < IV < I
3. Option 3: I < II < IV < III
4. Option 4: II < III < I < IV

The correct order of increasing stability, corresponding to increasing \( \Delta \), is I < II < IV < III. This implies complex I has the lowest \( \Delta \) and is thus least stable, while complex III has the highest \( \Delta \) and is most stable.

Conclusion: The increasing stability order, determined by \( \Delta \) value, is I < II < IV < III.