JEE Main 202623 JanuaryMorning Shift
- Exam
- JEE Main
- Year
- 2026
- Date
- 23 January
- Shift
- Morning Shift
- Subject
- Chemistry
- Chapter
- Coordination Compounds
JEE Main 2026 · 23 January · Morning Shift · Chemistry · Coordination Compounds
Given below are two statements : Statement I : [CoBr_ 4 ]^ 2- ion...
Given below are two statements :
Statement I: ion will absorb light of lower energy than \left[\mathrm{CoCl}_{4}\right]^{2-} ion, the energy separation between the two set of d-orbitals is more than \left[\mathrm{CoCl}_{4}\right]^{2-}$ ion.
In the light of the above statements, choose the correct answer from the options given below :
Statement I: ion will absorb light of lower energy than \left[\mathrm{CoCl}_{4}\right]^{2-} ion, the energy separation between the two set of d-orbitals is more than \left[\mathrm{CoCl}_{4}\right]^{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⁻ < Br⁻ < Cl⁻ < F⁻. Since Br⁻ is weaker than Cl⁻, [CoBr₄]²⁻ has smaller crystal field splitting (Δ) than [CoCl₄]²⁻. The d-d absorption energy equals the splitting energy, so [CoBr₄]²⁻ absorbs lower energy light. TRUE
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.
Statement I: Ligand field strength order is I⁻ < Br⁻ < Cl⁻ < F⁻. Since Br⁻ is weaker than Cl⁻, [CoBr₄]²⁻ has smaller crystal field splitting (Δ) than [CoCl₄]²⁻. The d-d absorption energy equals the splitting energy, so [CoBr₄]²⁻ absorbs lower energy light. TRUE
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.