Chemistry Transition Elements MDCAT 2018
PMDC Verified Question 53 of 68
The shape of \( [Co(NH_{3})_{6}]^{3+} \) complex is
A
Square planar
B
Tetrahedral
C
Linear
D
Octahedral
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Octahedral
Concept:

The geometry of a coordination complex is primarily determined by its coordination number (the total number of ligand donor atoms bound to the central metal).

Solution:

  • In the complex \([Co(NH_3)_6]^{3+}\), there are six ammine (\(NH_3\)) ligands attached to the central Cobalt (\(Co\)) ion.


  • A coordination number of 6 typically corresponds to an \(d^2sp^3\) or \(sp^3d^2\) hybridization.


  • Both of these hybridizations result in a symmetrical Octahedral spatial geometry.


Why other options are incorrect:

  • Square planar / Tetrahedral: Corresponds to a coordination number of 4.


  • Linear: Corresponds to a coordination number of 2.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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