JEE Chemistry 2023 Question with Solution

Given: The question asks which property cannot be explained by Crystal Field Theory (CFT).

Find: The correct option.

CFT explains several properties of transition metal complexes:

• Magnetic properties: it predicts magnetism from the number of unpaired electrons and ligand field strength.
• Colour of complexes: it explains colour through splitting of $d$-orbitals into $t_{2g}$ and $e_g$ levels, leading to electronic transitions.
• Stability of complexes: it accounts for stability through Crystal Field Stabilization Energy (CFSE).

However, CFT does not explain the order of the spectrochemical series, because that order is based on experimental observations and involves effects such as covalent bonding that are outside the scope of CFT.

The solution states the correct option is B, but this disagrees with the solution explanation and the listed options. Based on the working, the defensible answer is A.

The explanatory text clearly says that CFT cannot explain the order of the spectrochemical series. Among the given options, that statement corresponds to option A.

So although the page labels the answer as B, the worked explanation supports A. Therefore, the correct choice from the provided options is A.