The given observations are to be explained by the halogenation mechanism. Concept Introduction: ▸ Keto and enol form of carbonyl compounds are constitutional isomers. Inter-convertible keto and enol forms are tautomer. ▸ An enol and enolates can be formed by replacing the hydrogen at the α carbon. ▸ The α hydrogen can undergo halogen substitution at the α carbon in the presence of an acid and a base. ▸ When halogen substitution reaction takes place in the presence of an acid it is called as acid catalyzed halogenation reaction. ▸ When halogen substitution reaction takes place in the presence of a base it is called as base prompted halogenation reaction. ▸ In the base prompted halogenation reaction and acid catalyzed halogenation reaction slows rates are independent from the concentration of the halogens. ▸ The equimolar mixture of two enantiomers are called a racemic mixture. ▸ Racemization takes place at α hydrogen in the presence of acids or bases.

Question

8. Draw all the resonance forms for each of the following molecules or ions, and indicate the major contributor in each case, or if they are equivalent. (4.5 pts) (a) PH2 سمة

Answer 1

Question

Chapter 18, Problem 5PP

Interpretation Introduction

Interpretation:

The given observations are to be explained by the halogenation mechanism.

Concept Introduction:

▸ Keto and enol form of carbonyl compounds are constitutional isomers. Inter-convertible keto and enol forms are tautomer.

▸ An enol and enolates can be formed by replacing the hydrogen at the α carbon.

▸ The α hydrogen can undergo halogen substitution at the α carbon in the presence of an acid and a base.

▸ When halogen substitution reaction takes place in the presence of an acid it is called as acid catalyzed halogenation reaction.

▸ When halogen substitution reaction takes place in the presence of a base it is called as base prompted halogenation reaction.

▸ In the base prompted halogenation reaction and acid catalyzed halogenation reaction slows rates are independent from the concentration of the halogens.

▸ The equimolar mixture of two enantiomers are called a racemic mixture.

▸ Racemization takes place at α hydrogen in the presence of acids or bases.

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