Question

Choose the Incorrect option regarding valence bond theory of coordination compound.

• A. It does not give a quantitative interpretation of the thermodynamic stabilities of coordination compounds.
• B. It does not explain the colour exhibited by coordination compounds.
• C. It does not give quantitative interpretation of magnetic data.
• D. It does not distinguish between outer orbital and inner orbital complexes.

Hint:

A major success of VBT is the distinction between inner orbital complexes (\(d^2sp^3\)) and outer orbital complexes (\(sp^3d^2\)).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Valence Bond Theory (VBT) was an early attempt to explain bonding in coordination compounds, but it has several known limitations, such as failing to explain electronic spectra (color) or providing precise thermodynamic values.

Step 2: Detailed Explanation:
• (A) Correct statement: VBT is qualitative and does not predict the stability constants of complexes.
• (B) Correct statement: VBT does not account for d-d transitions, which are responsible for the color of complexes.
• (C) Correct statement: While it predicts whether a complex is paramagnetic or diamagnetic, it does not quantitatively calculate magnetic moments (e.g., orbital contribution).
• (D) Incorrect statement: VBT does distinguish between inner orbital complexes (using $(n-1)d$ orbitals) and outer orbital complexes (using $nd$ orbitals). This is one of the primary features of the theory.

Step 3: Final Answer:
Option (D) is the incorrect statement.