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Chemistry Question 47 – NEET-UG 2026

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Given below are two statements: Statement-I : [Fe(ox)3]3− is chiral. Statement-II : trans−[Cr(H2O)2(ox)2]− is chiral. (Given : oxH2=HOOC−COOH) In light of the above statements, choose the most appropriate answer from the options given below:

A molecule or ion is chiral if it is non-superimposable on its mirror image. This property is often associated with the absence of a plane of symmetry or a center of inversion.

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Ninja Strategy•Symmetry Element Check

Quickly identify the presence or absence of a plane of symmetry in each complex to determine chirality, especially for common octahedral geometries like M(AA)3 and Ma2(AA)2.

Step 1: Analyze Statement-I for Chirality✦ Active

The complex in Statement-I is [Fe(ox)3]3−. This is an octahedral complex of the M(AA)3 type, where 'ox' (oxalate, C2O42−) is a symmetrical bidentate ligand. Complexes of this type are known to be chiral, existing as Δ and Λ enantiomers, and do not possess a plane of symmetry or a center of inversion. Therefore, Statement-I is correct.

💡 Teacher's Secret Hint

Complexes with three bidentate ligands are inherently chiral.

Step 2: Analyze Statement-II for Chirality○ Expand

The complex in Statement-II is trans−[Cr(H2O)2(ox)2]−. This is an octahedral complex of the Ma2(AA)2 type, where 'a' is H2O and 'AA' is 'ox'. In the trans isomer, the two monodentate ligands (water molecules) are positioned opposite to each other (at 180∘). This arrangement creates a plane of symmetry passing through the central metal ion and the two trans water ligands, bisecting the two oxalate ligands. The presence of this plane of symmetry makes the trans isomer achiral (optically inactive). Therefore, Statement-II is incorrect.

💡 Teacher's Secret Hint

The presence of a plane of symmetry makes a molecule achiral.

Step 3: Conclude based on the analysis○ Expand

Based on the analysis, Statement-I is correct, and Statement-II is incorrect. This corresponds to option (3).

💡 Teacher's Secret Hint

Combine the findings for both statements to select the correct option.

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