Q12 / 75 · JEE Main 2026 (02 April Shift 1) · Chemistry
Match List - I with List - II.
List - I
Chromium (III) Complexes
(en = ethylene diamine) List - II
$\Delta_0$ (cm$^{-1}$) A. $[Cr(CN)_6]^{3-}$ I. $15,060$ B. $[CrF_6]^{3-}$ II. $17,400$ C. $[Cr(H_2O)_6]^{3+}$ III. $22,300$ D. $[Cr(en)_3]^{3+}$ IV. $26,600$
Choose the correct answer from the options given below :
| List - I Chromium (III) Complexes (en = ethylene diamine) | List - II $\Delta_0$ (cm$^{-1}$) |
|---|---|
| A. $[Cr(CN)_6]^{3-}$ | I. $15,060$ |
| B. $[CrF_6]^{3-}$ | II. $17,400$ |
| C. $[Cr(H_2O)_6]^{3+}$ | III. $22,300$ |
| D. $[Cr(en)_3]^{3+}$ | IV. $26,600$ |
Choose the correct answer from the options given below :
- AA-I, B-II, C-III, D-IV
- BA-II, B-III, C-IV, D-I
- CA-III, B-IV, C-I, D-II
- Correct answerDA-IV, B-I, C-II, D-III
Solution
The crystal field splitting energy $\Delta_0$ depends on the strength of the ligand.
According to the spectrochemical series, the order of ligand strength is $F^- < H_2O < en < CN^-$.
Thus, the order of $\Delta_0$ for the given complexes is $[CrF_6]^{3-} < [Cr(H_2O)_6]^{3+} < [Cr(en)_3]^{3+} < [Cr(CN)_6]^{3-}$.
Matching with the given values:
$[CrF_6]^{3-}$ has the minimum $\Delta_0 = 15,060$ cm$^{-1}$ (B $\rightarrow$ I).
$[Cr(H_2O)_6]^{3+}$ has $\Delta_0 = 17,400$ cm$^{-1}$ (C $\rightarrow$ II).
$[Cr(en)_3]^{3+}$ has $\Delta_0 = 22,300$ cm$^{-1}$ (D $\rightarrow$ III).
$[Cr(CN)_6]^{3-}$ has the maximum $\Delta_0 = 26,600$ cm$^{-1}$ (A $\rightarrow$ IV).
This corresponds to A-IV, B-I, C-II, D-III.
Answer: A-IV, B-I, C-II, D-III
According to the spectrochemical series, the order of ligand strength is $F^- < H_2O < en < CN^-$.
Thus, the order of $\Delta_0$ for the given complexes is $[CrF_6]^{3-} < [Cr(H_2O)_6]^{3+} < [Cr(en)_3]^{3+} < [Cr(CN)_6]^{3-}$.
Matching with the given values:
$[CrF_6]^{3-}$ has the minimum $\Delta_0 = 15,060$ cm$^{-1}$ (B $\rightarrow$ I).
$[Cr(H_2O)_6]^{3+}$ has $\Delta_0 = 17,400$ cm$^{-1}$ (C $\rightarrow$ II).
$[Cr(en)_3]^{3+}$ has $\Delta_0 = 22,300$ cm$^{-1}$ (D $\rightarrow$ III).
$[Cr(CN)_6]^{3-}$ has the maximum $\Delta_0 = 26,600$ cm$^{-1}$ (A $\rightarrow$ IV).
This corresponds to A-IV, B-I, C-II, D-III.
Answer: A-IV, B-I, C-II, D-III
Hence, the correct answer is option: 'D'.