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Question #44576
The Question
An aqueous solution of a coordination compound with the empirical formula \ce{M(en)2Cl3} (where \ce{M^{3+}} is a transition metal) is treated with excess \ce{AgNO3(aq)} at , yielding exactly of \ce{AgCl(s)} precipitate per mole of the compound. The complex cation exists in multiple stereoisomeric forms. Due to the anisotropic ligand field, the crystal field splitting energy () is highly sensitive to the geometry. In the \textit{trans}-isomer, the weaker axial field results in (where is the spin-pairing energy). Conversely, in the \textit{cis}-isomer, the synergistic ligand field yields .
Calculate the sum of the numerical values of: (i) The total number of stereoisomers of the complex cation. (ii) The number of unpaired electrons in the high-spin isomer. (iii) The spin-only magnetic moment (in BM) of the optically active isomer(s).
Options
- A.
7
- B.
6
- C.
11.90
- D.
5
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Mechanism_Trap
Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.
Concepts Behind This Question
Optical Isomerism Logic|Valence Bond Theory Hybridization|Spin-Only Magnetic Moment
Why This Question Is Tricky
Common Mistakes
Tests the intersection of Crystal Field Theory and Stereochemistry.
Students typically rely on the heuristic that complexes with strong-field ligands (like ethylenediamine) are universally low-spin (, diamagnetic).
The trap introduces a geometry-dependent ligand field where the trans-isomer is forced into a high-spin state () while the cis-isomer remains low-spin ().
To solve, the student must decouple the magnetic moment calculation from the empirical formula and correctly map the high/low spin states to the specific chiral (cis) and achiral (trans) geometries.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Coordination Compounds - Class 12 |
| Concept | Optical Isomerism Logic |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |