Question

$d\pi - p \pi$ bond present in :

• A. $NO_2^-$
• B. $NO_3^-$
• C. $PO_4^{3-}$
• D. $CO_3^{2-}$

Answer 1

The Correct Option is C

To determine which compound has a d\pi - p\pi bond, we need to understand what this type of bonding involves. The d\pi - p\pi bond is a type of bond formed between the d orbital of one atom and the p orbital of another. This kind of bonding is often seen in compounds where transition metals or heavier main group elements form bonds with electronegative atoms.

1. Let's analyze each compound:
   • NO_2^−: The nitrite ion has nitrogen and oxygen. Here, the bonding involves p\pi - p\pi interaction, since both elements are non-metals with only p orbitals available for bonding.
   • NO_3^−: The nitrate ion also involves nitrogen and oxygen, similar to the nitrite ion. Thus, it also shows p\pi - p\pi bonding.
   • PO_4^{3-}: The phosphate ion involves phosphorus and oxygen. Phosphorus, being a heavier element (third period), has available d orbitals that can participate in d\pi - p\pi bonding with the p orbitals of oxygen.
   • CO_3^{2-}: The carbonate ion involves carbon and oxygen. Carbon only has p orbitals, so it forms p\pi - p\pi bonds with oxygen.
2. Conclusion:

From the analysis, the compound PO_4^{3-} is most likely to have a d\pi - p\pi bond due to the ability of phosphorus to utilize its d orbitals for bonding with the oxygen atoms. Therefore, the correct answer is PO_4^{3-}.