Q79. - Organic Chemistry

Question

Question: The N atom in ${\mathbf{CH}}_{\mathbf{3}}{\mathbf{CONH}}_{\mathbf{2}}$   (acetamide) is ${\mathbf{sp}}^{\mathbf{2}}$  hybridized, even though it is surrounded by four groups. Using this information, draw a diagram that shows the orbitals used by the atoms in the $\mathbf{-}{\mathbf{CONH}}_{\mathbf{2}}$ portion of acetamide, and offer an explanation as to the observed hybridization

Step-by-Step Solution

Answer

Answer

                                                   

Step-by-Step Solution Step 1: Resonance structures

The combination of one or more structures used to portray the chemical bonding in molecules is known as the resonance structure.

Step 2: The resonance structures of acetamide

                                 

                                                              Resonance structures of acetamide

 

The nitrogen is ${\mathrm{sp}}^2$   hybridized because it is involved in resonance with the carbonyl group.

 

The unhybridized p orbitals on nitrogen, carbon, and oxygen overlap laterally, and the lone pair on the nitrogen atom is delocalized on these three atoms.

Step 3: Orbital diagram representing the bonding in - CONH 2

The unhybridized p orbitals on nitrogen, carbon, and oxygen overlap laterally, and the lone pair on the nitrogen atom is delocalized on these three atoms.

                                                                       

                                                 Orbitals involved in   bonding $-{\mathrm{CONH}}_2$

To attain additional stability by virtue of resonance, delocalization of electrons is compulsory, which is possible only if nitrogen is ${\mathrm{sp}}^2$  hybridized.