JEE Main202623 January 2026Morning ShiftChemistryCoordination CompoundsActual
Given below are two statements : Statement I : [ CoBr ₄ ]²⁻ ion will absorb light of lower energy than [ CoCl ₄ ]²⁻ ion. Statement II : In [ CoI ₄ ]²⁻ ion, the energy separation between the two set of d-orbitals is more than [ CoCl ₄ ]²⁻ ion. In the light of the above statements, choose the correct answer from the options given below :
Options
- ABoth Statement I and Statement II are false
- BBoth Statement I and Statement II are true
- CStatement I is false but Statement II is true
- DStatement I is true but Statement II is false
Correct answer
D. Statement I is true but Statement II is false
Step-by-step solution
Crystal field theory explains d-d transitions in complexes based on ligand field strength. Statement I: Ligand field strength order is I⁻ Statement II: I⁻ is a much weaker field ligand than Cl⁻. Therefore, [CoI₄]²⁻ has smaller crystal field splitting than [CoCl₄]²⁻, not larger. The energy separation in [CoI₄]²⁻ is less than in [CoCl₄]²⁻. FALSE Statement I is true but Statement II is false.