NEET  >  Chemistry Class 12  >  Physical & Chemical Properties of Aldehydes & Ketones

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Document Description: Physical & Chemical Properties of Aldehydes & Ketones for NEET 2022 is part of Chemistry Class 12 preparation. The notes and questions for Physical & Chemical Properties of Aldehydes & Ketones have been prepared according to the NEET exam syllabus. Information about Physical & Chemical Properties of Aldehydes & Ketones covers topics like and Physical & Chemical Properties of Aldehydes & Ketones Example, for NEET 2022 Exam. Find important definitions, questions, notes, meanings, examples, exercises and tests below for Physical & Chemical Properties of Aldehydes & Ketones.

Introduction of Physical & Chemical Properties of Aldehydes & Ketones in English is available as part of our Chemistry Class 12 for NEET & Physical & Chemical Properties of Aldehydes & Ketones in Hindi for Chemistry Class 12 course. Download more important topics related with notes, lectures and mock test series for NEET Exam by signing up for free. NEET: Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET
1 Crore+ students have signed up on EduRev. Have you?

 Physical properties of acids and acid derivatives :

1. Boiling point :

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

The high boiling points of carboxylic acids is the result of formation of a stable hydrogen-bonded dimer.

 Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

   Hydrogen bonded acid dimer

Solubility :

Carboxylic acids form hydrogen bonds with water and the lower molecular –weight carboxylic acids (upto 4 carbon atoms) are miscible with water.

Acid derivatives (esters, acid chlorides, anhydride, nitriles and amides) are soluble in organic solvents such as alcohols, ethers, chlorinated alkanes and aromatic hydrocarbons.

Methods of preparation of carboxylic acids:

1. Synthesis of carboxylic acids by the carboxylation of Grignard's reagent:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

 

2- Synthesis of Carboxylic acids by the hydrolysis of nitriles:

 Mechanism :

 Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

  Nitrile                                                                  carboxylic acid

 

Chemical Reactions

1. Acidic strength %

Acidity of carboxylic acids :-

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Ex.
Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Ex. HCOOH > CH3COOH > CH3-CH2-COOH

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Ex. Relative acid strength is:-
RCOOH > HOH > ROH > HC = CH > NH3 > RH

Note:- Acidity of acids is compared by comparing stability of conjugate base.

2- Reaction involving removal of proton from –OH group.

1.Action with blue litmus : All carboxylic acids turn blue litmus red.
2.Reaction with metals :

2 CH3 COOH + 2Na  → 2CH3COONa + H2
                                      Sodium acetate

2CH3 COOH + Zn → (CH3COO)2 Zn + H2
                                   Zinc acetate

3.Reaction with alkalies :
CH3 COOH + NaOH → CH3 COONa + H2O

4.Reaction with carbonates and bicarbonates :
2CH3COOH + Na2CO3 → 2CH3 COONa + CO2 + H2O
CH3COOH + NaHCO→ CH3COONa + CO2 + H2O

Reaction of carboxylic acid with aqueous sodium carbonate solution produces brisk effervescence. However, most phenols do not produce effervescence. Therefore, the reaction may be used to distinguish between carboxylic acids and phenols.

5.Reaction with Grignard's reagent :

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Note: A stronger acid displaces a weaker acid from salt of the weaker acid.

Ex. CH3COOH (Stronger acid) + CH3ONa → CH3 COONa + CH3 —OH (WeakerAcid)

Ex. CH3COOH (stronger acid) + NaHCO3 →  CHCOONa + HCO3 (Weaker acid) →  H2O + CO2

3. Reaction involving replacement of –OH group

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(i) Formation of acid chlorides : 

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET
Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(2)  Fisher Esterification:

Carboxylic acid react with alcohol to form esters through a condensation reaction known as esterification.

General Reaction : 

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Specific Example:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Mechanism:
 Acid catalysed esterfication:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET
                                   Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

If we follow the forward path in this mechanism, we have the mechanism for the acid catalysed esterification for an acid. If however, we follow the reverse reactions, we have the mechanism for the acid catalysed hydrolysis of an ester. Acid catalysed ester hydrolysis gives:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(3)  Formation of amides: 

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(4)  Formation of acid anhydride: 

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(4) Decarboxylation reactions:

1   Soda-lime decarboxylation :

 General reaction:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

2. Decarboxylation of  β- keto carboxylic acids :

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET- keto acid

3) Kolbe's electrolysis:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET
Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET
Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(II) R.  +  R→ R - R

If n is the number of carbon atoms in the salt of carboxylic acid, the alkane formed has 2(n-1) carbon atoms.

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

4) Hunsdiecker Reaction (Brome-decarboxylation):

R-COOAg + Br2  → R-Br + CO2 + AgBr

Mechanism:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

5. HVZ Reaction (Halogenation of aliphatic acids and Substituted acids):

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

                              Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Carboxylic Acid Derivatives

Closely related to the carboxylic acids and to each other are a number of chemical families known as functional derivatives of carboxylic acids : acid chloride, anhydrides, amides, and esters. These derivatives are compounds in which the -OH of a carboxyl group has been replaced by–Cl, -OOCR, -NR2 or –OR.

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET   Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET   Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET


They all contain the acyl group , Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(A)    Acid halides:

Methods of preparation of Acyl halides:

(i) RCOOH + PCl5  → RCOCl + POCl3  + HCl

(ii) 3RCOOH + PCl3 → 3RCOCl + H3PO3

(iii) RCOOH + SOCl2 Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET RCOCl +SO2  + HCl

Ex.  
Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Ex.   
Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

 Chemical Reactions: 

1. Reaction with carboxylic acids:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

2. Reaction with alcohols:

Acyl chlorides react with alcohols to form esters. The reaction is typically carried out in the presence of pyridine.

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

 

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

 Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

3) Hydrolysis:

 Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

4) Reaction of acid halide with organometallic compounds:

(a) with Grignard's reagent-

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET           

(b) Reaction with Gilmann's reagent-

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

 

5) Reduction of acid halide:

(a)  Reduction LiAlH4

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET           

(b) Reduction with H2/Pd/BaSO Rosenmund reduction-

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

 

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(B)   Acid amides

Methods of preparation of acids amides:

1. By reaction of esters with ammonia and amines.

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Ammonia is more nucleophilic than water, making it possible to carry out this reaction using aqueous ammonia.

Ex.Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

 

2. From acid halides:

RCOCl + 2NH3 → RCONH2 + NH4Cl

3. From anhydride:

(RCO)2O + 2NH3 → RCONH2  + RCOO NH4

4. From esters:

RCOOR + NH3 → RCONH2  + R’OH

 5. From ammonium salt of carboxylic acid:

RCOONH4 Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET RCONH2 + H2O

CH3 COONH4 Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET CH3CONH2

6. From cyanides:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

7.

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Chemical Reactions:

(1)  Hoffmann rearrangement:

General reaction-

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(2) Hydrolysis of amides-

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

In acid, however, the amine is protonated, giving an ammonium ion, R2Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Summary of Reaction of Amide:

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(C) Esters

Methods of Preparation:

(i) CH3 COOH + C2H5OH Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET CH3COOC2 H5  + H2O
Acetic acid

 C6H5COOH + CH3OH Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET C6H5 COOCH3  + H2

(ii) CH3 COCl + C2H5OH Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET CH3COOC2H5  + HCl

Alcohols react with acyl chlorides by nucleophilic acyl substitution to yield esters. These reactions are typically performed in the presence of a weak base such as pyridine.

 Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Summary of reaction of esters :

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

(D) Acid anhydrides

Methods of Preparation of acid anhydrides:

1- From carboxylic acids

Ex.
CH3COOH + HOOCCH3  Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET CH3CO.O.COCH3  + H2O
Acetic acid                                        Acetic anhydride

Ex.

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Ex.     

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

 

2. From acid and acid halide

Ex.      CH3COOH + CH3COCl Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET CH3 CO.O.COCH3 + HCl

Ex.      CH3COCl + CH3COONa Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET CH3CO.O.COCH3  + NaCl

Chemical Reactions

1. Reaction with aromatic compounds (Friedel crafts acylation)-

 

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

 

2. Reaction with alcohols-

Ex.

   Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

 

3.  Reaction with ammonia and amines-

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

4. Hydrolysis-

 Acid anhydrides react with water to yield two carboxylic acids. Cyclic anhydrides yield dicarboxylic acids.

          Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

            Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

5. Heating Effects: 

 a. Heating effect on monocarboxylic acid

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

b. Heating effect on dicarboxylic acid

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

c. Heating effect on Hydroxy acids

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

1- Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEETHydroxy acid

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEETPhysical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET       

2. Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEETHyroxy acid

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET    

3- Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEETHydroxy acid

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

Since 4 or 8 membered rings are less stable therefore β-Hydroxy acids on heating produce α,β unsaturated carboxylic acid.

4- An α -Hyroxy acid

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

 5. Heating effect on esters

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET 

This reaction follows syn elimination & Hoffman product is formed.

The document Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET is a part of the NEET Course Chemistry Class 12.
All you need of NEET at this link: NEET
157 videos|362 docs|261 tests
Download as PDF

How to Prepare for NEET

Read our guide to prepare for NEET which is created by Toppers & the best Teachers

Download free EduRev App

Track your progress, build streaks, highlight & save important lessons and more!

Related Searches

Semester Notes

,

Extra Questions

,

Free

,

Important questions

,

Sample Paper

,

study material

,

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

,

Exam

,

video lectures

,

practice quizzes

,

Summary

,

pdf

,

MCQs

,

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

,

Previous Year Questions with Solutions

,

past year papers

,

ppt

,

shortcuts and tricks

,

Viva Questions

,

Objective type Questions

,

mock tests for examination

,

Physical & Chemical Properties of Aldehydes & Ketones Notes | Study Chemistry Class 12 - NEET

;