NCERT Solutions Class 12 Chemistry - Chapter 8 Aldehydes, Ketones and Carboxylic Acids - PDF Download

NCERT solutions for Class 12 chemistry chapter 8 will help students to revise the entire chapter and score high marks. We are going to talk about the organic compounds with carbon oxygen double bonds called the carbonyl group. The carbonyl group is one of the most important functional groups in organic chemistry.

Once you've finished studying this unit, you'll be able to write the common names and IUPAC names for aldehydes and ketones, as well as the structures of compounds with functional groups like carbonyl and carboxyl groups. You'll also be able to explain the important methods of preparation and reactions of these classes of compounds, compare physical properties and chemical reactions of aldehydes and ketones with their structures, explain the mechanisms of a few selected reactions of aldehyde and Ketone, understand the factors that affect the acidity of Carboxylic Acids and their reactions.

NCERT Solutions for Class 12 Chemistry Chapter 8 Subtopics

8.1 Nomenclature and Structure of Carbonyl group: in this section, common names and IUPAC names of aldehydes and ketones and structure of carbonyl group will be discussed in this section.

8.2 Preperation of Aldehydes and Ketones: 
Some important methods for the preparation of aldehydes and ketones are discussed in this section:

   8.2.1 Preparation of Aldehydes and Ketones

• By oxidation of alcohols

• By dehydrogenation of alcohols

• From hydrocarbons

     8.2.2 Preparation of Aldehydes

• From acyl chloride

• From nitriles and esters

• From hydrocarbons

     8.2.3 Preparation of Ketones 

• From acyl chloride

• From nitriles

• From benzene or substituted benzenes

8.3  Physical Properties: In this section, physical properties of aldehydes and ketones like boiling point, solubility, odour etc. will be discussed.

8.4 Chemical Reactions: In this section, important chemical reaction of Aldehydes and Ketones are discussed which are given below:

• Nucleophilic addition reactions

• Reduction

• Oxidation

• Reactions due to ɑ-hydrogen

• Other reaction

8.5 Uses of Aldehydes and Ketones: Aldehydes and ketones are used in the chemical industry to make things like solvents, starting materials, and reagents for making other stuff. Formaldehyde is well-known for being a 40% formaldehyde solution used to keep biological samples safe and to make things like bakelite (a formaldehyde resin), Urea-formaldehyde glue, and other plastics.

8.6 Nomenclature and Structure of Carboxyl group: Carboxylic acid is one of the first organic compounds to be isolated from the natural environment, which is why most of them are referred to by their common names. Most common names end in the letter –ic and are derived from the names of the natural sources in Latin or Greek.

8.7 Method of Preparation of Carboxylic Acids 
Some important methods of preparation of carboxylic acids are discussed in this section

• From primary alcohols and aldehydes

• From alkylbenzenes

• From nitriles and amides

• From Grignard reagents

• From acyl halides and anhydrides

• From esters

8.8 Physical properties: In this section, physical properties of carboxylic acids like boiling point, solubility, odour etc. will be discussed.

8.9 Chemical Reactions
Some important chemical reactions of carboxylic acids are discussed in this section

• Reactions involving cleavage of O-H bond

• Reactions involving cleavage of C-OH bond

• Reactions involving -COOH group

• Substitution reactions in the hydrocarbon part

8.10 Uses of Carboxylic Acids
The chemical compounds methanoic acid and ethanoic acid are widely utilized in a variety of industries, including rubber, textiles, dyes, leather, and electroplating. Additionally, ethanoic acid is employed as a solvent and as a vinegar in the food industry.

Key Features of Class 12 Chemistry Chapter 8 NCERT Solutions

• Carbon-containing organic compounds, such as alkyl esters, ketones, and carbonyl acids, are important classes of organic compounds that contain carbonyl groups. Because these carbonyl-containing molecules are highly polar, they are prepared at higher boiling points than hydrocarbons, as well as weakly polar compounds like ethers of similar molecular weights. The lower members of carbonyl compounds are water soluble, as they form hydrogen bonding with water.

• Higher members, due to their large hydrophobic carbon atoms, are not soluble in water. However, they are soluble in a variety of common organo-solvents. Aldehydes are prepared from primary alcohols dehydrogenated or oxidized, and acetyl halides are controlled or selectively reduced.

• To prepare ketones, secondary alcohols are oxidized to ketones and alkynes are hydrated to ketones. Acyl chloride is also used in the preparation of ketones by reaction of acyl chloride and dialkyl cadmium. One of the best ways to prepare aromatic ketones is to acylate aromatic hydrocarbon with acyl chloride or anhydride.

• Aldehydes or ketones have carbonyl groups. These carbonyl groups may be reduced to methylene groups by clemmensen reduction and wolff-kishner reduction, respectively. Aldehydes can be easily oxidised to carbonyl acids with mild oxidizing reagents like Tollens' reagent and Fehling's reagent. Carbonyl oxidation is used to differentiate aldehydes from ketones. Carbonyl acids are oxidised to primary alcohols.

Frequently Asked Questions

Question 1: What are aldehydes, ketones and carboxylic acids?

Answer 1: A few different types of organic compounds have functional groups. Aldehydes and ketones have carbonyl groups (C = O). Aldehydes' carbonyl groups are on the ends of their carbon chains, while ketones have their carbonyl groups in the middle of their carbon chains. Carbonyl acids, on the other hand, have both carbonyl and hydroxyl groups attached to one carbon.

Question 2: How can you differentiate between aldehydes and ketones?

Answer 2: The structural difference between aldehydes and ketones lies in the presence of carbonyl groups at the ends of the carbon chain and carbonyl groups in the center of the carbon chain.