Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store
NEET 2022 | Class 12

NEET Aldehydes Ketones and Carboxylic Acids Chapter

Get plus subscription and access unlimited live and recorded courses
Introduction to Aldehydes Ketones and Carboxylic Acids Notes

Introduction to Aldehydes Ketones and Carboxylic Acids Notes


Last updated date: 04th Dec 2024
Total views: 276.3k
Views today: 4.76k

In NEET Chemistry, the topic “Aldehydes, Ketones and carboxylic acids” is very essential. Aldehydes, ketones, and carboxylic acids (COOH) are found in large amounts in both plants and animals. They (R-CHO. R-CO-R and COOH) serve a crucial function in life's metabolic processes. They are used to flavour a variety of foods and medications.


As a result, the total weightage of this chapter in the NEET exams is up to 4 percent. In this aldehydes ketones and carboxylic acids notes, aldol condensation, Grignard reaction and Cannizzaro Reaction are a few of the concepts that are covered in this article. 


Important Topics of Aldehydes Ketones and Carboxylic Acids

  • Acid anhydride

  • Aldehydes

  • Ester 

  • Aldol Condensation

  • ketone

  • Acyl halide

  • Cannizzaro reaction 

  • Carboxylic acid

  • Amide


Important Concepts of Aldehydes Ketones and Carboxylic Acids


Tollen’s test of aldehyde and ketone

The Tollens' test is a chemical reaction that distinguishes aldehydes from ketones because aldehydes may be oxidized to a carboxylic acid whereas ketones cannot.

Acid Anhydride

The elimination of water molecules from an acid produces an acid anhydride, which is a chemical substance. The functional group R(CO)O(CO)R' is found in organic acid anhydrides.

Acyl Halide

An acyl halide is a group formed from an oxoacid, including inorganic acids, by removing one or more hydroxyl groups.

Amide

Amides are functional groups in which a carbonyl carbon (C=O) atom is linked to a nitrogen (N) atom, as well as hydrogen (H) or carbon atom (C), by a single bond.

Ester

As in the substitution reaction between a carboxylic acid and an alcohol, an ester is a chemical molecule produced from an acid (organic or inorganic) in which at least one –OH hydroxyl group is replaced by a –O– alkyl (alkoxy) group.

Carboxylic acid

A carboxylic acid is an organic molecule in which a carbon (C) atom is double-bonded to an oxygen (O) atom and a hydroxyl group (OH) is single-bonded.


Aldehydes Ketones and Carboxylic Acids

The carbonyl group is one of the most important functional groups in organic chemistry because it contains a carbon-oxygen double bond (>C=O). The carbonyl group is connected to a carbon and hydrogen in aldehydes, while it is bonded to two carbon atoms in ketones. Carboxylic acids are carbonyl compounds in which the carbonyl group is linked to oxygen.

Aldehydes and ketones belong to a class of compounds having general formula CnH2nO and are represented as RCHO and RR'CO respectively.


Methods of Preparation of Aldehydes

1. Oxidation of Primary Alcohols

Oxidation can be affected with acidic K2Cr2O7 or with PCC (Pyridine Chlorochromate, mild oxidising agent) in CH2Cl2


2. Oxidation of Methylbenzenes


3. By Heating a Mixture of the Calcium Salts of Formic Acid and any one of its Homologues


Methods of Preparation of Ketones

1. Oxidation of Secondary Alcohols


2. By Heating the Calcium Salt of any Monocarboxylic Acid other than Formic Acid


3. Friedel – Crafts Acylation

Used for the preparation of aliphatic aromatic ketones or aromatic ketones.


Methods of Preparation of Carboxylic Acids

1. By Oxidation of Primary Alcohol


2. By hydrolysis of Cyanides


Physical Properties of Aldehydes and Ketones 

  • These are the polar compounds due to the presence of a carbonyl group.

  • They have higher boiling points than non-polar compounds of comparable molecular weights.

  • They are soluble in water.


Physical Properties of Carboxylic Acids

  • Carboxylic acids have polar molecules that form hydrogen bonds.

  • The first four members are water miscible. The greater the acid, the less soluble it is. Benzoic acid, the most basic aromatic acid, has far too many carbon atoms to be soluble in water.


Chemical Properties of Aldehydes, Ketones and Carboxylic Acids

1. Oxidation

(a)


(b) Tollen's Reagent

 A specific oxidant for RCHO is Ag(NH3)2+. Ketones do not give this reaction


(c) Strong Oxidants

Ketones resist mild oxidation, but with strong oxidants at a high temperature, they undergo cleavage of the  C-C bond on either side of the carbonyl group.


(d) Haloform Reaction is Shown by Methyl Ketones.

CH3COR are readily oxidized by NaOI (NaOH + I2) to iodoform, CHI3, and RCO2Na.


2. Reduction

(a) Reduction to Alcohols

Reduction to alcohols can be achieved either by hydrogenation in the presence of Pt or Pd or by LiAlH4/NaBH4.


(b) Reduction to Hydrocarbons


3. Addition Reactions of Nucleophiles

The carbon of the carbonyl group is electrophilic and thus initially attacked by a nucleophile.



(a) Addition of Grignard Reagent



(b) Addition of Hydrogen Cyanide



(c) Addition of Sodium Bisulfite

Bisulfite compound formation is confined to aldehydes, methyl ketones and some cyclic ketones.


(d) Nucleophilic Addition of Derivatives of Ammonia


4. Addition of Alcohols

The carbonyl compounds react with alcohols, R'OH, to yield hemiacetals.


5. Cannizzaro Reaction


6. Aldol Condensation


7. Perkin Condensation


8. Beckmann Rearrangement

The acid-catalyzed conversion of ketoximes to N substituted amides is known as Beckmann rearrangement.


Chemical Properties of Carboxylic Acid

1. The carboxylic acids react with metal to liberate hydrogen and are soluble in NaOH and NaHCO3 solutions. 

2. Carboxylic acid reacts with halogenated compounds and forms acid halide.


3. Carboxylic acid gets reduced to alcohol.


4. Hell Volhard Zelinsky Reaction- Aliphatic carboxylic acids react with Br2 or Cl2 in presence of phosphorus (or phosphorus halides) to give haloacids.



5. Schmidt Reaction- Carboxylic acids react with hydrazoic acid in presence of concentrated H2SO4 to give amine.

6. Benzoic acid is attacked by the usual electrophilic reagents Chlorine, Bromine, Nitric and sulphuric acids to give m-derivatives.


Solved Examples/Problems From the Chapter: Organic Compound Containing Oxygen

1. Names the reagent that is use in the transformation of Hexan-1-ol to hexanal:

Sol: The oxidation of Hexan-1-ol to hexanal takes place in the presence of a mild oxidizing agent. One of the most widely used mild oxidizing agents is  PCC (Pyridinium chlorochromate). Its structural formula is C5H5NH+CrO3Cl-

Key Points: Mild oxidizing agent is used for the conversion of alcohol to aldehyde or ketone While strong oxidizing agent is used to convert alcohol to carboxylic acid.


2. Write structures of the products of the given reaction.


Sol: The product formed in the above reaction will be propiophenone. The structure of this compound is given below. This reaction takes place in the presence of lewis acid and non polar medium.


Key Points: The reaction given above is an acylation reaction.


Solved Problems of Previous Year Question from the Chapter: Aldehyde, Ketones, and Carboxylic Acid

1. An alkene on ozonolysis gives methanal as one of the products. Its structure is :

Options:


Ans: The correct answer is option 3.


Trick: The given reaction is an ozonolysis reaction. The trick to solve this question in less time is just break the double bond and attach oxygen with the double bonded carbon molecules.


2. Identify compound X in the following sequence of reactions :


Options:


Ans: The correct answer is option 3.


Trick: Two hydroxyl groups on the same carbon are unstable and lead to dehydration and form an aldehyde or ketone (formation of double bond oxygen).


3. What is the IUPAC name of the organic compound formed in the following chemical reaction?


(1) 2-methyl propan-2-ol 

(2) pentan-2-ol 

(3) pentan-3-ol 

(4) 2-methyl butan-2-ol

Ans: The correct answer is option 4.


Trick: The given reaction is a grignard reaction. 


Practice Questions

1. Give names of the reagents that is used to bring the given transformations:

Cyclohexanol to cyclohexanone 

(Ans: PCC.)

2. Would you expect benzaldehyde to be more reactive or less reactive in nucleophilic addition reactions than propanal? Explain your answer. 

(Ans: Less reactive due to resonance)


Conclusion:

In this article, we have provided important information regarding the chapter aldehyde, ketones and carboxylic acid such as important concepts, reactions, etc. Students should work on more solved examples and previous year question papers for securing good grades in the NEET exams.

See More
NEET 2024 Important Dates

NEET 2024 Important Dates

View All Dates
NEET 2024 exam date and revised schedule have been announced by the NTA. NEET 2024 will now be conducted on 5 May 2024, and the exam registration starts on 9 February 2024 and closes on 9 March 2024. You can check the complete schedule on our site. Furthermore, you can check NEET 2024 dates for application, admit card, exam, answer key, result, counselling, etc along with other relevant information.
See More
View All Dates
NEET Information

NEET Information

Application Form
Eligibility Criteria
Reservation Policy
Admit Card
NTA has announced the NEET 2024 application form release date on the official website https://neet.nta.nic.in/. The NEET 2024 Application Form is available on the official website for online registration from 9 February 2024 to 9 March 2024. Besides the NEET 2024 application form release date, learn about the application process, steps to fill out the form, how to submit it, the exam date sheet, etc online. Check our website for more details.
NEET 2024 applicants should be aware of the eligibility criteria before applying for the exam. NTA has released all the relevant information on the official website, i.e. https://neet.nta.nic.in/. NEET 2024 aspirants should have passed Class 12th or any other equivalent qualifying examination in 2023, or 2022, or students appearing in the Class 12th final exam in 2024 can also apply. For further details, visit our website.
As per the union government’s norms, NTA has released the NEET 2024 reservation criteria for different candidates’ categories (SC/ST/OBC/PwD), All India Quota, State Government Quota, Deemed Universities, and more. You can check more details on the Vedantu website.
NEET 2024 Admit Card will be released by the NTA in the 4th week of April 2024. Candidates can download the NEET admit card and hall ticket from the NEET official website i.e. https://neet.nta.nic.in/. For more details on the NEET admit card 2024, candidates can check Vedantu's official website.
NEET 2024 Study Material

NEET 2024 Study Material

View NEET Syllabus in Detail
Download full syllabus
Download full syllabus
View NEET Syllabus in Detail
NEET 2024 Study Material

NEET 2024 Study Material

View all study material for NEET
All
Physics
Chemistry
Biology
See All
NEET Question Papers

NEET Question Papers

NEET 2024 Book Solutions and PDF Download

NEET 2024 Book Solutions and PDF Download

View all NEET Important Books
Biology
NCERT Book for Class 12 Biology
Physics
NCERT Book for Class 12 Physics
Chemistry
NCERT Book for Class 12 Chemistry
Physics
H. C. Verma Solutions
See All
NEET 2024 Mock Tests

NEET 2024 Mock Tests

View all mock tests
NEET 2024 free online mock test series for exam preparation are available on the Vedantu website for free download. Practising these mock test papers of Physics, Chemistry and Biology prepared by expert teachers at Vedantu will help you to boost your confidence to face the NEET 2024 examination without any worries. The NEET test series for Physics, Chemistry and Biology that is based on the latest syllabus of NEET and also the Previous Year Question Papers.
See More
NEET 2024 Cut Off

NEET 2024 Cut Off

NEET Cut Off
NTA is responsible for the release of the NEET 2024 cut off score. The qualifying percentile score might remain the same for different categories. According to the latest trends, the expected cut-off mark for NEET 2024 is 50% for general category candidates, 45% for physically challenged candidates, and 40% for candidates from reserved categories. For the general category, NEET qualifying marks for 2024 ranged from 715-117 general category, while for OBC/SC/ST categories, they ranged from 116-93 for OBC, 116-93 for SC and 116-93 for ST category.
See More
NEET 2024 Results

NEET 2024 Results

The NEET 2024 result will be published by NTA on https://neet.nta.nic.in/ in the form of a scorecard on 14 June 2024. The scorecard will include the roll number, application number, candidate's personal details, and the percentile, marks, and rank of the candidate. Only those candidates who achieve the NEET cut-off will be considered qualified for the exam.
See More
Rank List
Counselling
Marks and Rank
NEET 2024 state rank lists will be released by the Medical Counselling Committee (MCC) for admissions to the 85% state quota and to all seats in private medical and dental colleges. NEET 2024 state rank lists are based on the marks obtained in medical entrance exams. Candidates can check the NEET 2024 state rank list on the official website or our site.
The Medical Counselling Committee (MCC) will conduct NEET 2024 counselling at www.mcc.nic.in. There will be two rounds of counselling for admission under 15% All India Quota (AIQ), deemed and central universities, AIIMS, JIPMER, ESIC, and AFMC. A mop-up round of NEET counselling will be conducted excluding 15% AIQ seats, while the dates of NEET counselling for 85% state quota seats will be announced by the respective state authorities.
As per the union government’s norms, NTA has released the NEET 2024 reservation criteria for different candidates’ categories (SC/ST/OBC/PwD), All India Quota, State Government Quota, Deemed Universities, and more. Previously, the Indian Government has provided NEET reservations to OBC (27%) and EWS (10%) candidates under All India Quota (AIQ). You can check more details on the Vedantu website.
NEET 2024 Top Colleges

NEET 2024 Top Colleges

View all NEET 2024 Top Colleges
Want to know which Engineering colleges in India accept the NEET 2024 scores for admission to Engineering? Find the list of Engineering colleges accepting NEET scores in India, compiled by Vedantu. 1990 Colleges are accepting NEET Score. It includes 706 Medical, 323 Dental, 914 AYUSH, and 47 BVSc & AH colleges. Also find more details on Fees, Ranking, Admission, and Placement.
See More
question-image

FAQs on NEET Aldehydes Ketones and Carboxylic Acids Chapter

FAQ

1. In the NEET examination, what is the contribution of the aldehyde, ketones and carboxylic acids chapter?

Approximately 2-3 questions from this chapter appear on the exam, covering roughly 12 marks and accounting for 3-4 percent of the total marks.

2. What are the main points to remember while tackling problems involving aldehyde, ketones and carboxylic acids?

Students should practice writing the mechanism of the reaction for solving the questions in the NEET exam. By practicing the mechanism of the reaction, the concept behind the product formation will become clear thus giving answers will take less time in exam.

3. What are the important topics that need to be covered from this chapter to score good marks in the NEET exam?

Canizaro reaction, aldol condensation reaction, ozonolysis of alkenes and reaction with grignard reagent are the main topics from this chapter that comes in NEET exam.