Chapter 18, Problem 40PP

Interpretation Introduction

Interpretation For the given compounds, most acidic compound should be identified.

Concept introduction:

• For stronger acids, its conjugate base is more stable
• Conjugate base is formed by the deprotonation of the parent acid
• A five membered ring will be aromatic if it contains six $\text{π}$ electrons. In order to have six $\text{π}$ electrons, one of the carbon atoms must possess two electrons. It should be a carbanion.
• Aromatic compounds are more stable than non-aromatic compound
• The conditions for aromatic compound are,

1. 1. 1. It should be planar
   2. 2. It must obey the Huckel’s rule

The requirement of an odd number of electron pair is called Huckel’s rule. A     compound can only be aromatic if the number of $\text{π}$ electron in the ring is 2, 6,10,14,18 and so on. This series of number can be expressed mathematically as $\text{4n+2}$, where n should be an integer and the compound is aromatic.

1. 3. Continuous conjugated $\text{π}$ system(all carbon should be in ${\text{sp}}^{\text{2}}$ hybridized state)

If any compound which doesn’t satisfy one of the above condition then the compound is not aromatic