Chapter 14, Problem 14.75GP

Interpretation Introduction

Interpretation:

The alkene should be identified from the given alcohol undergoes dehydration. Cis and trans alkene should be mentioned

Concept introduction:

Dehydration reaction:

Removal of water molecule from the reaction when the alcohol is treated with strong acid like sulfuric acid.

Alcohol is reaction with concentrated sulfuric acid, first alcohol gets protonated forms carbocation (more stable carbocation) followed by elimination of proton (${\text{H}}^{\text{+}}$) yields alkene as a product. The stability of carbocation is given below,

Tertiary carbocation is more stable than the secondary, secondary carbocation is more stable than primary.

In dehydration reaction, sulfuric acid is act as a proton donor, and which is used to protonate the alcohol and makes carbocation therefore sulfuric acid is the driving force of the reaction. Dehydration reaction will not go without acid (sulfuric acid).

Cis and Trans alkene:

In 1,2-disubstituted alkenes, if the two alkyl groups ($\text{R}$) are on the same side of the $\text{C = C}$ is called as cis alkene.

In 1,2-disubstituted alkenes, if the two alkyl groups ($\text{R}$) are on the opposite side of the $\text{C = C}$ is called as Trans alkene.