Chemistry Ncert Solutions Class 12 Chapter 12

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes Ketones and Carboxylic Acids includes all the important topics with detailed explanation that aims to help students to understand the concepts better. Students who are preparing for their Class 12 exams must go through NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes Ketones and Carboxylic Acids. Going through the solutions provided on this page will help you to know how to approach and solve the problems.

Students can also find NCERT intext, exercises and back of chapter questions. Also working on Class 12 Chemistry Chapter 12 Aldehydes Ketones and Carboxylic Acids NCERT Solutions will be most helpful to the students to solve their Homeworks and Assignments on time. Students can also download NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes Ketones and Carboxylic Acids PDF to access them even in offline mode.

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes Ketones and Carboxylic Acids

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes Ketones and Carboxylic Acids are been solved by expert teachers of CBSETuts.com. All the solutions given in this page are solved based on CBSE Syllabus and NCERT guidelines.

INTEXT Questions

Question 1.
Write the structures of the following compounds.

  1. α-Methoxypropionaldehyde
  2. 3-Hydroxybutanal
  3. 2-Hydroxycyclopentanecarbaldehyde
  4. 4-Oxopentanal
  5. Di-sec.butyl ketone
  6. 4-Fluoroacetophenone

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 1

Question 2.
Write the structures of the products of the following reactions :
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 2
Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 3

Question 3.
Arrange the following compounds in increasing order of their boiling points.
CH3CHO, CH3CH2OH, CH3OCH3, CH3CH2CH3
Solution:
CH3CH2CH3 < CH3OCH3 < CH3CHO < CH3CH2OH

Question 4.
Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.

  1. Ethanal, Propanal, Propanone, Butanone.
  2. Benzaldehyde, p-Tolualdehyde,

p – Nitrobenzaldehyde, Acetophenone. Hint: Consider steric effect and electronic effect.
Solution:

  1. Butanone < Propanone < Propanal < Ethanal
  2. Acetophenone < p-Tolualdehyde, Benzaldehyde < p-Nitrobenzaldehyde

Question 5.
Predict the products of the following reactions :
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 4
Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 5

Question 6.
Give the IUPAC names of the following compounds :
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 6
Solution:

  1. 3-Phenylpropanoic acid
  2. 3-Methylbut-2-enoic acid
  3. 2-Methylcyclopentanecarboxylic acid
  4. 2,4,6-Trinitrobenzoic acid

Question 7.
Show how each of the following compounds can be converted to benzoic acid.

  1. Ethylbenzene
  2. Acetophenone
  3. Bromobenzene
  4. Phenylethene (Styrene)

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 7
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 8

Question 8.
Which acid of each pair shown here would you expect to be stronger ?
(i) CH3CO2H or CH2FCO2H
(ii) CH2FCO2H or CH2ClCO2H
(iii) CH2FCH2CH2CO2H or CH3CHFCH2CO2H
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 9
Solution:
(i) H2CFCOOH will be stronger of the two. The presence of electronegative F atom at the α-C causes electron withdrawal from the COOH and facilitates the release of H+.
(ii) CH2FCO2H is a stronger acid for the same reason as stated above. F is more electronegative than Cl, so it withdraws electrons from the carboxyl group to a greater extent.
(iii) CH3CHFCH2COOH is stronger. Although both the givenacidshaveFatomin them, it is the proximity of F in CH3CHFCH2COOH to the COOH group which makes it more acidic.
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 10

NCERT Exercises

Question 1.
What is meant by the following terms? Give an example of the reaction in each case.

  1. Cyanohydrin
  2. Acetal
  3. Semicarbazone
  4. Aldol
  5. Hemiacetal
  6. Oxime
  7. Ketal
  8. Imine
  9. 2,4-DNP derivative
  10. Schiff's base

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 11
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 12
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 13
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 14
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 15

Question 2.
Name the following compounds according to IUPAC system of nomenclature :

  1. CH3CH(CH3)CH2CH2CHO
  2. CH3CH2COCH(C2H5)CH2CH2Cl
  3. CH3CH=CHCHO
  4. CH3COCH2COCH3
  5. CH3CH(CH3)CH2C(CH3)2COCH3
  6. (CH3)3CCH2COOH
  7. OHCC6H4CHO-p

Solution:

  1. 4-Methylpentanal
  2. 6-Chloro-4-ethylhexan-3-one
  3. But-2-en-1-al
  4. Pentane-2, 4-dione
  5. 3, 3, 5-Trimethylhexan-2-one
  6. 3, 3-Dimethylbutanoic acid
  7. Benzene-1, 4-dicarbaldehyde

Question 3.
Draw the structures of the following compounds.

  1. 3-Methylbutanal
  2. p-Nitropropiophenone
  3. p-Methylbenzaldehyde
  4. 4-Methylpent-3-en-2-one
  5. 4-Chloropentan-2-one
  6. 3-Bromo-4-phenylpentanoic acid
  7. p, p'-Dihydroxybenzophenone
  8. Hex-2-en-4-ynoic acid

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 16

Question 4.
Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give also common names.
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 17
Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 18

Question 5.
Draw structures of the following derivatives.

  1. The 2,4-dinitrophenylhydrazone of benz- aldehyde
  2. Cyclopropanone oxime
  3. Acetaldehydedimethylacetal
  4. The semicarbazone of cyclobutanone
  5. The ethylene ketal of hexan-3-one
  6. The methyl hemiacetal of formaldehyde

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 19

Question 6.
Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.

  1. PhMgBr and then H3O+
  2. Tollens'reagent
  3. Semicarbazide and weak acid
  4. Excess ethanol and acid
  5. Zinc amalgam and dilute hydrochloric acid

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 20
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 21
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 22

Question 7.
Which of the following compounds would undergo aldol condensation, which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction.

  1. Methanal
  2. 2-Methylpentanal
  3. Benzaldehyde
  4. Benzophenone
  5. Cyclohexanone
  6. 1-Phenylpropanone
  7. Phenylacetaldehyde
  8. Butan-1-ol
  9. 2,2-Dimethylbutanal

Solution:
Aldol condensation is shown by those aldehydes or ketones which have at least one α-H atom while Cannizzaro reaction is undergone by aldehydes that have no α-H atom.
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 23
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 24
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 25

Question 8.
How will you convert ethanal into the following compounds?

  1. Butane-1,3-diol
  2. But-2-enal
  3. But-2-enoic acid

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 26

Question 9.
Write structural formulas and names of four possible aldol condensation products from propanal and butanal. In each case, indicate which aldehyde acts as nucleophile and which as an electrophile
Solution:
The possible products of aldol condensation from propanal and butanal are
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 27
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 28

Question 10.
An organic compound with the molecular formula C9H10O forms 2,4-DNP derivative, reduces Tollens' reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1, 2-benzenedicarboxylic acid. Identify the compound.
Solution:
(i) It is given that the compound reduces Tollens' reagent. This proves that the compound is an aldehyde. Further, the fact that it undergoes Cannizzaro reaction shows that it lacks an α-H atom.

(ii) On oxidation it yields 1,2-benzenedicarboxylic acid. This shows that it is an o-substituted benzaldehyde. The only possible structure for the compound is :
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 29
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 30

Question 11.
An organic compound (A) (molecular formula C8H16O2) was hydrolysed with dilute sulphuric acid to give a carboxylic acid (B) and an alcohol (C). Oxidation of (C) with chromic acid produced (8). (C) on dehydration gives but-1-ene. Write equations for the reactions involved.
Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 31
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 32

Question 12.
Arrange thefollowing compounds in increasing order of their property as indicated :

  1. Acetaldehyde, Acetone, Di-tert-butyl ketone, Methyl fert-butyl ketone (reactivity towards HCN)
  2. CH3CH2CH(Br)COOH,CH3CH(Br)CH2COOH, (CH3)2CHCOOH, CH3CH2CH2COOH (acid strength)
  3. Benzoic acid, 4-Nitrobenzoic acid, 3,4-Dinitrobenzoic acid, 4-Methoxybenzoic acid (acid strength)

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 33
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 34

Question 13.
Give simple chemical tests to distinguish between the following pairs of compounds.

  1. Propanal and Propanone
  2. Acetophenone and Benzophenone
  3. Phenol and Benzoic acid
  4. Benzoic acid and Ethyl benzoate
  5. Pentan-2-one and Pentan-3-one
  6. Benzaldehyde and Acetophenone
  7. Ethanal and Propanal

Solution:
The given set of compounds may be distinguish by the following reaction.
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 35
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 36
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 37

Question 14.
How will you prepare the following compounds from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom

  1. Methyl benzoate
  2. m-Nitrobenzoic acid
  3. p-Nitrobenzoic acid
  4. Phenylacetic acid
  5. p-Nitrobenzaldehyde

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 38
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 39
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 40
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 41
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 42

Question 15.
How will you bring about the following conversions in not more than two steps?

  1. Propanone to Propene
  2. Benzoic acid to Benzaldehyde
  3. Ethanol to 3-Hydroxybutanal
  4. Benzene to m-Nitroacetophenone
  5. Benzaldehyde to Benzophenone
  6. Bromobenzene to 1 -Phenylethanol
  7. Benzaldehyde to 3-Phenyipropan-1 -ol
  8. Benzaldehyde to a-Hydroxyphenylacetic acid
  9. Benzoic acid to m-Nitrobenzyl alcohol

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 43
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 44
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 45
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 46
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 47

Question 16.
Describe the following :

  1. Acetylation
  2. Cannizzaro reaction
  3. Cross-aldol condensation
  4. Decarboxylation

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 48
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 49
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 50
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 51
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 52

Question 17.
Complete each synthesis by giving missing starting material, reagents or products
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 53
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 54
Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 55
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 56
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 57

Question 18.
Give plausible explanation for each of the following :

  1. Cyclohexanone forms cyanohydrin in good yield but 2, 2,6 trimethylcyclohexa- none does not.
  2. There are two – NH2 groups in semicarbazide. However, only one is involved in the formation of semicarbazones.
  3. During the preparation of esters from a carboxylic acid and an alcohol in the presence of an acid catalyst, the water or the ester should be removed as soon as it is formed.

Solution:
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 58
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 59
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 60

Question 19.
An organic compound contains 69.77% carbon, 11.63% hydrogen and rest, oxygen. The molecular mass of the compound is 86. It does not reduce Tollens' reagent but forms an addition compound with sodium hydrogensulphite and give positive iodoform test. On vigorous oxidation it gives ethanoic and propanoic acid. Write the possible structure of the compound.
Solution:
(a) The given compound does not reduce Tollens' reagent which implies that it is not an aldehyde.
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 61
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 62

Question 20.
Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol. Why?
Solution:
(i) Phenoxide ion has the following resonating structures :
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 63
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 64
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 65
(iii) The negative charge that rests on the electronegative O atom in carboxylate ion. We know that the presence of negative charge on an electronegative atom makes the ion more stable. For the same reason RCOO is more stable than the phenoxide ion where the oxygen has no negative charge on it. For the above two reasons carboxylate ion is more stable and has higher acidity than phenol.

Now that you are provided all the necessary information regarding NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes Ketones and Carboxylic Acids and we hope this detailed NCERT Solutions are helpful.

NCERT Solutions for Class 12 Chemistry

Chemistry Ncert Solutions Class 12 Chapter 12

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