Chapter 15, Problem 15.79EP

(a)

Interpretation Introduction

Interpretation:

The inorganic product formed when butanal undergoes Tollen’s test has to be given.

Concept Introduction:

In organic chemistry, oxidation reaction is referred to the number $\text{C}-\text{O}$ bonds increase and/or number of $\text{C}-\text{H}$ bonds decrease.

In organic chemistry, reduction reaction is referred to the number $\text{C}-\text{O}$ bonds decrease and/or number of $\text{C}-\text{H}$ bonds increase.

Alcohols undergo oxidation reaction and reduction reaction.  This depends upon the number of hydrogen atoms that is bonded to the alpha carbon atom.  Primary and secondary alcohol undergoes oxidation reaction while tertiary alcohol does not undergo oxidation reaction.  Primary alcohols undergo oxidation to give aldehyde and carboxylic acid as product.  Secondary alcohol undergoes oxidation to give ketone as the product.

Aldehyde undergoes oxidation to give carboxylic acid as the product while ketone does not undergo oxidation reaction.

Tollen’s test:

This is also known as silver mirror test.  The reagent that is used in Tollen’s test is silver nitrate and ammonia in water.  Aldehyde reacts with Tollen’s reagent, where the silver ion is reduced to silver metal and the aldehyde is oxidized to carboxylic acid.

Ketone does not undergo Tollen’s test to deposit silver metal.

Benedict’s test:

This test is also similar to Tollen’s test.  In this test, ${\text{Cu}}^{\text{2+}}$ metal ion is used as oxidizing agent.  The ${\text{Cu}}^{\text{2+}}$ ion is reduced to ${\text{Cu}}^{\text{+}}$ ion while the aldehyde is oxidized to carboxylic acid.  ${\text{Cu}}_{\text{2}}\text{O}$ is precipitated as brick-red solid.  Ketone does not answer the Benedict’s test.  This is because ketone are not oxidized.

Answer to Problem 15.79EP

The inorganic product formed is silver metal.

Explanation of Solution

Aldehydes undergo Tollen’s test.  The product formed when aldehyde undergo oxidation is a carboxylic acid.  The general oxidation reaction for aldehyde can be given as,

Given aldehyde is butanal and the structure can be given as shown below,

This on reaction with Tollen’s reagent gives carboxylic acid and silver metal as the product.  The structure of the inorganic product formed and the complete reaction can be given as shown below,

Silver metal is formed as the inorganic product when butanal undergoes Tollen’s test.

Conclusion

The inorganic product formed is given.

(b)

Interpretation Introduction

Interpretation:

The inorganic product formed when 2-butanone undergoes Tollen’s test has to be given.

Concept Introduction:

In organic chemistry, oxidation reaction is referred to the number $\text{C}-\text{O}$ bonds increase and/or number of $\text{C}-\text{H}$ bonds decrease.

In organic chemistry, reduction reaction is referred to the number $\text{C}-\text{O}$ bonds decrease and/or number of $\text{C}-\text{H}$ bonds increase.

Alcohols undergo oxidation reaction and reduction reaction.  This depends upon the number of hydrogen atoms that is bonded to the alpha carbon atom.  Primary and secondary alcohol undergoes oxidation reaction while tertiary alcohol does not undergo oxidation reaction.  Primary alcohols undergo oxidation to give aldehyde and carboxylic acid as product.  Secondary alcohol undergoes oxidation to give ketone as the product.

Aldehyde undergoes oxidation to give carboxylic acid as the product while ketone does not undergo oxidation reaction.

Tollen’s test:

This is also known as silver mirror test.  The reagent that is used in Tollen’s test is silver nitrate and ammonia in water.  Aldehyde reacts with Tollen’s reagent, where the silver ion is reduced to silver metal and the aldehyde is oxidized to carboxylic acid.

Ketone does not undergo Tollen’s test to deposit silver metal.

Benedict’s test:

This test is also similar to Tollen’s test.  In this test, ${\text{Cu}}^{\text{2+}}$ metal ion is used as oxidizing agent.  The ${\text{Cu}}^{\text{2+}}$ ion is reduced to ${\text{Cu}}^{\text{+}}$ ion while the aldehyde is oxidized to carboxylic acid.  ${\text{Cu}}_{\text{2}}\text{O}$ is precipitated as brick-red solid.  Ketone does not answer the Benedict’s test.  This is because ketone are not oxidized.

Answer to Problem 15.79EP

No inorganic product is obtained as 2-butanone does not undergo Tollen’s test.

Explanation of Solution

Aldehydes undergo Tollen’s test.  The product formed when aldehyde undergo oxidation is a carboxylic acid.  The general oxidation reaction for aldehyde can be given as,

Given compound is a ketone that is 2-butanone and the structure can be given as shown below,

This on reaction with Tollen’s reagent does not give oxidized product.  Therefore, no reaction takes place when 2-butanone reacts with Tollen’s reagent.

No inorganic product is formed when 2-butanone undergoes Tollen’s test.

Conclusion

No reaction takes place when 2-butanone undergoes Tollen’s test.

(c)

Interpretation Introduction

Interpretation:

The inorganic product formed when 3-methylpentanal undergoes Benedict’s test has to be given.

Concept Introduction:

In organic chemistry, oxidation reaction is referred to the number $\text{C}-\text{O}$ bonds increase and/or number of $\text{C}-\text{H}$ bonds decrease.

In organic chemistry, reduction reaction is referred to the number $\text{C}-\text{O}$ bonds decrease and/or number of $\text{C}-\text{H}$ bonds increase.

Alcohols undergo oxidation reaction and reduction reaction.  This depends upon the number of hydrogen atoms that is bonded to the alpha carbon atom.  Primary and secondary alcohol undergoes oxidation reaction while tertiary alcohol does not undergo oxidation reaction.  Primary alcohols undergo oxidation to give aldehyde and carboxylic acid as product.  Secondary alcohol undergoes oxidation to give ketone as the product.

Aldehyde undergoes oxidation to give carboxylic acid as the product while ketone does not undergo oxidation reaction.

Tollen’s test:

This is also known as silver mirror test.  The reagent that is used in Tollen’s test is silver nitrate and ammonia in water.  Aldehyde reacts with Tollen’s reagent, where the silver ion is reduced to silver metal and the aldehyde is oxidized to carboxylic acid.

Ketone does not undergo Tollen’s test to deposit silver metal.

Benedict’s test:

This test is also similar to Tollen’s test.  In this test, ${\text{Cu}}^{\text{2+}}$ metal ion is used as oxidizing agent.  The ${\text{Cu}}^{\text{2+}}$ ion is reduced to ${\text{Cu}}^{\text{+}}$ ion while the aldehyde is oxidized to carboxylic acid.  ${\text{Cu}}_{\text{2}}\text{O}$ is precipitated as brick-red solid.  Ketone does not answer the Benedict’s test.  This is because ketones are not oxidized.

Answer to Problem 15.79EP

The inorganic product formed is ${\text{Cu}}_{\text{2}}\text{O}$ when 3-methylpentanal undergoes Benedict’s test.

Explanation of Solution

Aldehydes undergo Benedicts’s test.  The product formed when aldehyde undergo oxidation is a carboxylic acid.  The general oxidation reaction for aldehyde can be given as,

Given aldehyde is 3-methylpentanal and the structure can be given as shown below,

This on reaction with Tollen’s reagent gives carboxylic acid and Copper(I) oxide as the product.  The inorganic product formed and the complete reaction can be given as shown below,

${\text{Cu}}_{\text{2}}\text{O}$ is the inorganic product formed when 3-methylpentanal undergoes Benedict’s test.

Conclusion

The inorganic product formed when 3-methylpropanal undergoes Benedict’s test is given.

(d)

Interpretation Introduction

Interpretation:

The inorganic product formed when 3-pentanone undergoes Benedict’s test has to be given.

Concept Introduction:

In organic chemistry, oxidation reaction is referred to the number $\text{C}-\text{O}$ bonds increase and/or number of $\text{C}-\text{H}$ bonds decrease.

In organic chemistry, reduction reaction is referred to the number $\text{C}-\text{O}$ bonds decrease and/or number of $\text{C}-\text{H}$ bonds increase.

Alcohols undergo oxidation reaction and reduction reaction.  This depends upon the number of hydrogen atoms that is bonded to the alpha carbon atom.  Primary and secondary alcohol undergoes oxidation reaction while tertiary alcohol does not undergo oxidation reaction.  Primary alcohols undergo oxidation to give aldehyde and carboxylic acid as product.  Secondary alcohol undergoes oxidation to give ketone as the product.

Aldehyde undergoes oxidation to give carboxylic acid as the product while ketone does not undergo oxidation reaction.

Tollen’s test:

This is also known as silver mirror test.  The reagent that is used in Tollen’s test is silver nitrate and ammonia in water.  Aldehyde reacts with Tollen’s reagent, where the silver ion is reduced to silver metal and the aldehyde is oxidized to carboxylic acid.

Ketone does not undergo Tollen’s test to deposit silver metal.

Benedict’s test:

This test is also similar to Tollen’s test.  In this test, ${\text{Cu}}^{\text{2+}}$ metal ion is used as oxidizing agent.  The ${\text{Cu}}^{\text{2+}}$ ion is reduced to ${\text{Cu}}^{\text{+}}$ ion while the aldehyde is oxidized to carboxylic acid.  ${\text{Cu}}_{\text{2}}\text{O}$ is precipitated as brick-red solid.  Ketone does not answer the Benedict’s test.  This is because ketones are not oxidized.

Answer to Problem 15.79EP

No inorganic product is formed when 3-pentanone undergoes Benedict’s test.

Explanation of Solution

Aldehydes undergo Benedict’s test.  The product formed when aldehyde undergo oxidation is a carboxylic acid.  The general oxidation reaction for aldehyde can be given as,

Given compound is a ketone.  The name of ketone is 3-pentanone and the structure can be given as shown below,

This on reaction with Benedict’s reagent does not give oxidized product.  Therefore, no reaction takes place when 3-pentanone undergoes Benedict’s test.

No inorganic product is formed when 3-pentanone undergo Benedict’s test.

Conclusion

No reaction takes place when 3-pentanone undergoes Benedict’s test.