Question

: Draw all possible resonating structures of Benzaldehyde.

Answer 1

Hint: Resonance is basically movement of \[{\text{pi }}\] electron density. Benzaldehyde has 6 \[{\text{pi }}\] electrons which are alternate to each other and also a \[{\text{ - CHO}}\] , aldehyde group which contains double bonded oxygen. This group along with other 6 \[{\text{pi }}\] electrons takes part in resonance.

Complete step by step answer:
When a single Lewis structure is not able to explain all the properties of a molecule or compound, we have to draw different structures to explain all the properties of that compound. These structures are known as resonance structure. A resonance hybrid formed out of all the resonance structures is the most stable among all.
The stability of resonating structure depends on:
The structure with no charge is most stable.
The more are the number of \[{\text{pi }}\] electrons, the more is the stability.
 The lesser is the distance between opposite charges, the more stable is the resonance structure.
The more is the distance between unlike charges, the lower will be the stability of that resonating structure.
Negative charge is the most stable on more electronegative elements and positive charge is more stable on less electronegative elements.
The number of resonance structures varies depending upon the number of electrons it has. Now, if we look at benzaldehyde, the molecular formula of benzaldehyde is \[{{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{CHO}}\]. It is basically an aldehyde group substituted with one of the hydrogen atoms of benzene rings. Due to the presence of 3 alternate \[{\text{\pi }}\] bonds made with 6 electrons, the electrons circulate in the ring. The following are the resonating structures of Benzaldehyde.

Note:
is a colourless liquid with a molecular mass of \[{\text{106}}{\text{.124 g mo}}{{\text{l}}^{{\text{ - 1}}}}\] . It has an almond like odour. It is mainly used to add odour and is sometimes used in cosmetic products. It is a very useful component in synthesis of various organic compounds. Through aldol condensation, it can be converted into cinnamaldehyde and styrene. It is also used as bee repellents.