Chapter 19, Problem 19.56P

Interpretation Introduction

(a)

Interpretation:

The product of the given reaction is to be predicted.

Concept introduction:

Chromic acid will oxidize a primary alcohol to a carboxylic acid or a secondary alcohol to a ketone. Chromic acid is prepared by dissolving sodium dichromate in an acidic solution.

Answer to Problem 19.56P

The product of the given reaction is

Explanation of Solution

The given reaction is

This is an example of an oxidation of a primary alcohol using sodium dichromate in aqueous acid. Chromic acid oxidizes a primary alcohol into corresponding carboxylic acid. The reaction is shown below:

Thus, carboxylic acid is the major product of the reaction.

Conclusion

Chromic acid oxidizes a primary alcohol into corresponding carboxylic acid.

Interpretation Introduction

(b)

Interpretation:

The product of the given reaction is to be predicted.

Concept introduction:

Chromic acid will oxidize a primary alcohol to a carboxylic acid or a secondary alcohol to a ketone. Chromic acid is prepared by dissolving sodium dichromate in an acidic solution.

Answer to Problem 19.56P

The product of the given reaction is

Explanation of Solution

The given reaction is

This is an example of an oxidation of a secondary alcohol using chromium trioxide in aqueous acid. Chromic acid oxidizes a secondary alcohol into corresponding ketone. The reaction is shown below:

Thus, ketone is the major product of the reaction.

Conclusion

Chromic acid oxidizes a secondary alcohol into corresponding ketone.

Interpretation Introduction

(c)

Interpretation:

The product of the given reaction is to be predicted.

Concept introduction:

Chromic acid will oxidize a primary alcohol to a carboxylic acid or a secondary alcohol to a ketone. Chromic acid is prepared by dissolving sodium dichromate in an acidic solution. Oxidation of chromic acid requires an $\text{OH}$ group that is attached to a carbon atom bonded to atleast one hydrogen atom. In tertiary alcohols, the carbon atom bonded to the $\text{OH}$ group has no hydrogen atom attached, thus, chromic acid cannot oxidize tertiary alcohols.

Answer to Problem 19.56P

There is no product of the given reaction, as chromic acid cannot oxidize tertiary alcohols.

Explanation of Solution

The given reaction is

This is an example of an oxidation of a secondary alcohol using chromium trioxide in aqueous acid. Chromic acid oxidizes a secondary alcohol into corresponding ketone. Oxidation of chromic acid requires an $\text{OH}$ group that is attached to a carbon atom bonded to atleast one hydrogen atom. In tertiary alcohols, the carbon atom bonded to the $\text{OH}$ group has no hydrogen atom attached, thus, chromic acid cannot oxidize tertiary alcohols.

There is no product of the given reaction, as chromic acid cannot oxidize tertiary alcohols.

Conclusion

Chromic acid cannot oxidize tertiary alcohols as in tertiary alcohols carbon atom which is attached to the hydroxyl group does not have any hydrogen atom attached.

Interpretation Introduction

(d)

Interpretation:

The product of the given reaction is to be predicted.

Concept introduction:

Chromic acid will oxidize a primary alcohol to a carboxylic acid or a secondary alcohol to a ketone. Aldehydes are oxidized to corresponding carboxylic acids using chromic acid but chromic acid is not sufficiently strong to oxidize ketones. Chromic acid is prepared by dissolving sodium dichromate in an acidic solution.

Answer to Problem 19.56P

The product of the given reaction is

Explanation of Solution

The given reaction is

This is an example of an oxidation reaction using chromic acid. The reactant molecule has both an aldehyde and a ketone group. Chromic acid oxidizes an aldehyde group into carboxylic acid but is not a sufficiently strong oxidizing agent to oxidize ketones.

The reaction is shown below:

Thus, a carboxylic acid is the major product of the reaction.

Conclusion

Chromic acid oxidizes an aldehyde to corresponding carboxylic acid but cannot oxidize a ketone.

Interpretation Introduction

(e)

Interpretation:

The product of the given reaction is to be predicted.

Concept introduction:

Like chromic acid, potassium permanganate is also used as an oxidizing agent. When treated with a basic solution of potassium permanganate (${\text{KMnO}}_4$), followed by aqueous acid: Primary alcohols and aldehydes are converted to carboxylic acids, while secondary alcohols are converted to ketones. However, tertiary alcohols do not undergo an oxidation reaction with ${\text{KMnO}}_4$.

Answer to Problem 19.56P

The product of the given reaction is

Explanation of Solution

The given reaction is

This is an example of an oxidation reaction using potassium permanganate. Like chromic acid, potassium permanganate is also used as an oxidizing agent. When treated with a basic solution of potassium permanganate (${\text{KMnO}}_4$), followed by aqueous acid, primary alcohols and aldehydes are converted to carboxylic acids, while secondary alcohols are converted to ketones. However, tertiary alcohols do not undergo an oxidation reaction with ${\text{KMnO}}_4$.

The reaction is shown below:

Thus, the major product of the given reaction is

Conclusion

When treated with a basic solution of potassium permanganate (${\text{KMnO}}_4$), followed by aqueous acid, primary alcohols and aldehydes are converted to carboxylic acids, while secondary alcohols are converted to ketones.

Interpretation Introduction

(f)

Interpretation:

The product of the given reaction is to be predicted.

Concept introduction:

Pyridinium chlorochromate (PCC) is a partial oxidizing agent. Oxidation of a primary alcohol by pyridinium chlorochromate (PCC) stops at the aldehyde because the reaction takes place in a nonaqueous medium. Pyridinium chlorochromate (PCC) oxidizes a primary alcohol to an aldehyde and a secondary alcohol to a ketone.

Answer to Problem 19.56P

The product of the given reaction is

Explanation of Solution

The given reaction is

This is an example of an oxidation reaction using pyridinium chlorochromate (PCC). Like othe oxidizing agents, pyridinium chlorochromate (PCC) oxidizes a primary alcohol to an aldehyde and a secondary alcohol to a ketone.

The reaction is shown below:

Thus, the major product of the given reaction is

Conclusion

Pyridinium chlorochromate (PCC) oxidizes a primary alcohol to an aldehyde and a secondary alcohol to a ketone.