Cis and trans isomers are possible in:

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Question

This question was previously asked in

DSSSB PGT Chemistry (Female) Official Paper (Held On: 06 Jul, 2018 Shift 1)

Answer 1

CONCEPT:

Cis and Trans Isomerism in Coordination Complexes

Cis and trans isomers are types of geometrical isomerism that occur in coordination complexes with specific spatial arrangements of ligands.
Cis isomers have two identical ligands adjacent to each other, while trans isomers have them opposite to each other.
Geometrical isomerism is observed in square planar and octahedral complexes.
For geometrical isomerism to occur, the complex must have at least two different types of ligands attached to the central metal ion.

EXPLANATION:

Analyzing the given options for cis and trans isomerism:
- Option 1: [Cr(NH₃)₆Cl]²⁺ - This complex has only one chloride ligand, and the rest are identical ammonia ligands. Geometrical isomerism is not possible.
- Option 2: [Cr(NH₃)₆]³⁺ - This complex has identical ammonia ligands, so geometrical isomerism is not possible.
- Option 3: [Cr(NH₃)₄Cl₂]⁺ - This complex has two chloride ligands and four ammonia ligands. Geometrical isomerism (cis/trans) is possible due to the spatial arrangement of the chloride ligands in the octahedral geometry.
- Option 4: [Cr(NH₃)Cl₃] - This complex is not octahedral; it is likely tetrahedral or distorted, and geometrical isomerism is not possible.
Correct Answer: Option 3 ([Cr(NH₃)₄Cl₂]⁺)

Therefore, cis and trans isomers are possible in [Cr(NH₃)₄Cl₂]⁺.