Chapter 8, Problem 12E

(a)

Interpretation Introduction

Interpretation: The mechanism for formation of the alcohol product should be drawn.

Concept introduction: Alkenes are regarded electron-rich and often undergo addition reaction in presence of electrophilic halo acids or nucleophilic sodium cyanide. The intermediate formed in former is tertiary carbocation and finally nucleophilic part of halo acid attacks in a rapid step to give addition product.

The product formed is governed by Markovnikov’s Rule. Rule suggests that negative part of halo acid HX must go to the carbon that has more alkyl substituents or less $\text{H}$ atoms. This is also justified as intermediate tertiary carbocation involved in this pathway is highly stable intermediate.

The order of relative stability of various possible carbocation species is as follows:

  

(b)

Interpretation Introduction

Interpretation: The expected product of reaction was carried out in methanol instead of water should be drawn.

Concept introduction: Alkenes are regarded electron-rich and often undergo addition reaction in presence of electrophilic halo acids or nucleophilic sodium cyanide. The intermediate formed in former is tertiary carbocation and finally nucleophilic part of halo acid attacks in a rapid step to give addition product.

The product formed is governed by Markovnikov’s Rule. Rule suggests that negative part of halo acid HX must go to the carbon that has more alkyl substituents or less $\text{H}$ atoms. This is also justified as intermediate tertiary carbocation involved in this pathway is highly stable intermediate.

The order of relative stability of various possible carbocation species is as follows: