Question

The following are some other organic reactions covered. Give an example to illustrate each type of reaction.

a. AddingH₂Oto an alkene yields an alcohol.

b. Primary alcohols are oxidized to aldehydes, which can be further oxidized to carboxylic acids.

c. Secondary alcohols are oxidized to ketones.

d. Reacting an alcohol with a carboxylic acid produces an ester.

Short answer

(a)With a hydrogen atom added to one carbon and hydroxyl group added to the other carbon of double bond

(b) Primary alcohols can be oxidized by some specific reagents to aldehydes, but often used oxidizing agents (potassium dichromate or potassium permanganate) are very powerful, so the primary alcohols are oxidized to carboxylic acids.

(c) Secondary alcohols can be oxidized to ketones using potassium dichromate under acidic conditions.

(d)The reaction of alcohol and carboxylic acid in acid is called Fisher's esterification.

Step-by-step solution

To Add H2O to an alkene:

An alkene reacts with water in the presence of an acid to form an alcohol. This reaction is called hydration, where a hydrogen atom is added to one carbon and hydroxyl group is added to the other carbon of double bond.

The figure below shows the reaction of but--ene with water in acidic conditions. The product is butan--ol.

Hence this reaction is called hydration, with a hydrogen atom adding to one carbon and hydroxyl group adding to the other carbon of double bond

Primary alcohols are oxidized to aldehydes:

Primary alcohols can be oxidized by some specific reagents to aldehydes, but often uses oxidizing agents such as (potassium dichromate or potassium permanganate) are meant to be very powerful, so the primary alcohols are oxidized to carboxylic acids.

An example of the oxidation of propanol to propanal and finally to propanoic acid is shown below.

Hence Primary alcohols can be oxidized by some specific reagents to aldehydes, but often uses oxidizing agents such as (potassium dichromate or potassium permanganate) which are very powerful, so that primary alcohols are oxidized to carboxylic acids.

Secondary alcohols are oxidized to ketones:

Secondary alcohols can be oxidized to ketones using potassium dichromate under acidic conditions.

The figure below shows the oxidation of butan--ol to butan--one.

Hence Secondary alcohols can be oxidized to ketones using potassium dichromate under acidic conditions.

Reaction of  an alcohol with a carboxylic acid :

The reaction of alcohol and carboxylic acid in acid is called Fisher's esterification.

In this reaction, esters are formed with the release of water. In order to shift the equilibrium of the reaction towards the ester, it is necessary to continuously remove the water.

An example of such a reaction is shown in the figure below.

Hence The reaction of alcohol and carboxylic acid in acid is called Fisher's esterification.