Question

Which of the following statement is not applicable to Valence Bond Theory?

• A. It does not give quantitative interpretation of magnetic data.
• B. It does not distinguish between weak and strong ligands.
• C. It explains the colour exhibited by coordination compounds.
• D. It does not make exact predictions regarding the structures of 4-coordinate complexes.

Hint:

VBT explains bonding and hybridisation in complexes, but colour, detailed magnetic behaviour, and ligand strength are better explained by Crystal Field Theory.

Answer 1

The Correct Option is C

Step 1: Recall the scope of Valence Bond Theory.
Valence Bond Theory explains coordination compounds on the basis of hybridisation of metal orbitals and overlap with ligand orbitals. It is useful for predicting the bonding and approximate geometry of many complexes. It also helps in understanding whether a complex is inner orbital or outer orbital and gives a rough idea about magnetic behaviour.
Step 2: Identify the limitations of Valence Bond Theory.
Valence Bond Theory has several important limitations. It does not provide a quantitative explanation of magnetic properties. It also cannot properly distinguish between weak ligands and strong ligands on the basis of crystal field splitting. Further, it is not always reliable in predicting the exact structures of 4-coordinate complexes, such as whether they are tetrahedral or square planar in all cases.
Step 3: Check the given statements carefully.

• (A) This is applicable to VBT because VBT does not give quantitative magnetic interpretation.
  
• (B) This is also applicable because VBT does not clearly distinguish weak and strong ligands.
  
• (C) This is not applicable because VBT does not explain the colour of coordination compounds. The colour is explained properly by Crystal Field Theory, not by VBT.
  
• (D) This is applicable because VBT does not make exact predictions regarding the structures of 4-coordinate complexes.
  

Step 4: Conclusion.
Hence, the statement that is not applicable to Valence Bond Theory is the statement that it explains the colour exhibited by coordination compounds.
Final Answer:It explains the colour exhibited by coordination compounds.