Question

Increasing order of stability of the resonance structures is: Choose the correct answer from the options given below:

• A. $D , C , A , B$
• B. C, D, A, B
• C. D, C, B, A
• D. $D , A , B$

Answer 1

The Correct Option is B

To determine the increasing order of stability of the given resonance structures, we need to evaluate each structure based on factors that influence resonance stability:

1. Octet Rule: Structures where atoms (especially carbon, nitrogen, and oxygen) have complete octets are generally more stable.
2. Charge Distribution: Less separation of charge is preferable. A structure with charges that are closer to each other, or neutral, is more stable.
3. Electronegativity: Negative charge is more stable on more electronegative atoms (e.g., oxygen or nitrogen), and positive charge is more stable on less electronegative atoms (e.g., carbon).
4. Resonance: Structures that can contribute more to resonance stabilization (delocalization of electrons) are more stable.

Let's analyze each given structure:

1. Structure A: There is charge separation with a positive and negative charge on adjacent atoms, which affects stability negatively.
2. Structure B: There is charge separation, and the positive charge is not on a highly electronegative atom, affecting its stability.
3. Structure C: There is less charge separation compared to A and B. Additionally, the negative charge is on a more electronegative atom.
4. Structure D: Although it has a positive charge on nitrogen, this structure is more stable than A and B due to less severe charge separation.

Based on these points, the increasing order of stability is:

1. C, D, A, B - Here C is the most stable due to less charge separation, followed by D with a positive charge on nitrogen, then A and B with higher charge separation.

So, the correct answer is: C, D, A, B.