⭕ Which of yhe following is most stable resonating structure ?

💠↪️  Refer to Attachment↩️

Here, In this case, you can remember the following key points:

Given compound is always more stable than its resonating structures (Charged species are less stable than uncharged)

No. of covalent bonds increases, stability increases.

Unlike charge separation (distance between opposite charges) decreases stability increases while like (distance between same charges) charges increases stability increases.

Negative charged is least stable at the less electronegative atom while it is more stable at a more electronegative atom.

 

Structures in which all the atoms have a complete valence shell of electrons (i.e., the octet) are more stable.

 

In the given question,

The resonating structures in option A and B are very unstable because positive charge is on sp2 hybridised carbon whose octet is incomplete

 

among option C and D, option D is more stable because positive charge is stable on nitrogen than oxygen atom.