NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids
NCERT Solutions for Class 12 Chemistry Chapter 12 – Free PDF Download
*As per the CBSE Prospectus 2023-24, this part has been renumbered as Section 8.
Chapter 12 Aldehydes Ketones and Carboxylic Acids
NCERT Answers for Class 12 Science Chapter 12 Aldehydes Ketones and Carboxylic Acids are a phenomenal wellspring of review material for CBSE Class 12 Science. These NCERT Answers for Class 12 Science are ready by profoundly experienced mentors as per the most recent CBSE Schedule 2023-24. Setting up the part notes is currently simple with the assistance of these arrangements.
The NCERT Answers for Class 12 Science incorporate every one of the significant inquiries according to the test perspective, similar to course reading arrangements, praiseworthy issues, worksheets, HOTS (Higher-Request Thinking Abilities) and MCQs. The NCERT Answers for Class 12 PDF for this part given beneath is clarified in a consistent way for assist understudies with figuring out the ideas easy.
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This section is an essential piece of Natural Science, and understudies ought to concentrate on this theme completely. Be that as it may, while setting up this section for their sheets, one could confront trouble in seeing every one of the ideas all alone. Without legitimate direction, they could wind up committing errors in their tests.
Aldehydes, Ketones and Carboxylic Acids Section Initially – Class 12 NCERT Solutions
- Aldehydes are ready by dehydrogenation or controlled oxidation of essential alcohols and controlled or specific decrease of acyl halides.
- Sweet-smelling aldehydes may likewise be ready by oxidation of (I) methylbenzene with chromyl chloride or CrO3 within the sight of acidic anhydride, (ii) formylation of arenes with carbon monoxide and hydrochloric corrosive within the sight of anhydrou aluminum chloride, and (iii) cuprous chloride or by hydrolysis of benzal chloride.
- Ketones are ready by oxidation of auxiliary alcohols and hydration of alkynes. Ketones are likewise ready by response of acyl chloride with dialkylcadmium.
- A decent technique for the planning of sweet-smelling ketones is the Friedel-Specialties acylation of fragrant hydrocarbons with acyl chlorides or anhydrides.
- Aldehydes and ketones go through nucleophilic expansion responses onto the carbonyl gathering with various nucleophiles, for example, HCN, NaHSO3, alcohols (or diols), alkali subordinates, and Grignard reagents.
- Aldehydes and ketones having no less than one – hydrogen, go through Aldol buildup within the sight of a base to give – hydroxyaldehydes (aldol) and – hydroxyketones(ketol), individually.
- Aldehydes having no – hydrogen go through Cannizzaro response within the sight of concentrated Soluble base.
- Aldehydes and ketones are diminished to alcohols with NaBH4 , LiAlH4 , or by synergist hydrogenation.
- The carbonyl gathering of aldehydes and ketones can be decreased to a methylene bunch by Clemmensen decrease or Wolff-Kishner decrease.
- Aldehydes are effortlessly oxidized to carboxylic acids by gentle oxidizing reagents like Tollens’ reagent and Fehling’s reagent. These oxidation responses are utilized to recognize aldehydes from ketones.
- Carboxylic acids are ready by the oxidation of essential alcohols, aldehydes and alkenes by hydrolysis of nitriles, and by treatment of Grignard reagents with carbon dioxide.
- Sweet-smelling carboxylic acids are additionally ready by side-chain oxidation of alkylbenzenes.
- Carboxylic acids are impressively more acidic than alcohols and a large portion of basic phenols.
- Carboxylic acids are decreased to essential alcohols with LiAlH4 , or better with diborane in ether arrangement and furthermore go through – halogenation with Cl2 and Br2 within the sight of red phosphorus (Damnation Volhard Zelinsky response).
Class 12 Chemistry NCERT Solutions Chapter 12 Aldehydes, Ketones and Carboxylic Acids – Important Questions
Question 12.1: What is meant by the following terms? Give an example of the reaction in
each case.
(i) Cyanohydrin
(ii) Acetal
(iii) Semicarbazone
(iv) Aldol
(v) Hemiacetal
(vi) Oxime
(vii) Ketal
(vii) Imine
(ix) 2,4-DNP-derivative
(x) Schiff’s base
Solution:
(I) Cyanohydrin:
Cyanohydrin is a natural compound with the equation RR’C(OH)CN, where alkyl or aryl gatherings might be R and R ‘.
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(i)
Within the sight of overabundance sodium cyanide (NaCN) as a forerunner to utilizing cyanohydrin, aldehydes and ketones respond with hydrogen cyanide (HCN). Such responses are delegated responses to cyanohydrins.
NCERT Answers for Class 12 Science Part 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(i)- 1
The helpful manufactured intermediates are Cyanohydrins.
(ii) Acetal:
The jewel dialkoxy alkanes at the terminal carbon molecule comprising of two gatherings of alkoxy are called Acetal. One bond is associated with an alkyl bunch, and the other to a hydrogen molecule.
NCERT Answers for Class 12 Science Part 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(ii)
Hemiacetals are shaped within the sight of dry HCl gas when aldehydes are treated with two monohydric liquor reciprocals. Moreover, hemiacetals respond with one more liquor atom to yield acetal.
NCERT Answers for Class 12 Science Part 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(ii)- 1
(iii) Semicarbazone:
Semicarbazone comes from aldehydes and ketones and is framed by the buildup response between a ketone or aldehyde and semicarbazide.
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(iii)
Semicarbarzones effectively distinguish and describe aldehydes and ketones.
(iv) Aldol:
An aldol is a β-hydroxy aldehyde or ketone. It is created within the sight of a base by the buildup response of two particles of the equivalent or a solitary particle, every one of two unique aldehydes or ketones.
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(iv)
(v) Hemiacetal:
Hemiacetals are α−alkoxyalcohols
NCERT Answers for Class 12 Science Part 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(v)
The general design of a hemiacetal.
Within the sight of dry HCl gas, aldehyde responds with one single atom of monohydrated liquor.
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(v)- 1
(vi) Oxime:
General equation – RR′CNOH
Where R is a natural side chain and R′ is either a natural side or hydrogen side chain. In the event that R′ is a natural side chain, ketoxime is known, and assuming R′ is H, it is called aldoxime.
NCERT Answers for Class 12 Science Part 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(vi)
Aldehydes or ketones structure oximes when treated with hydroxylamine in a feebly acidic medium.
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(vi)- 1
(vii) Ketal:
Ketals are pearl dialkoxyalkanes in which one carbon particle is contained two gatherings of alkoxy inside the chain. The other two carbon molecule bonds are connected with two alkyl gatherings.
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(vii)
A cyclic item is delivered within the sight of dry HCl gas, called ethylene glycol ketals when ketones respond with ethylene glycol.
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(vii)- 1
(viii) Imine:
Imines are substance intensifies which have a twofold connection between carbon-nitrogen.
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(viii)
The response of aldehydes and ketones with smelling salts or 1º-amines structures imine subsidiaries
NCERT Answers for Class 12 Science Section 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(viii)- 1
(ix) 2,4−DNP−derivative:
2, 4-dinitrophenylhydrazone are 2,4−DNP−derivatives which are delivered in a feebly acidic medium when aldehydes or ketones respond with 2,4−dinitrophenylhydrazine.
NCERT Answers for Class 12 Science Part 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(ix)
The 2,4−DNP subsidiaries are utilized to distinguish and portray aldehydes and ketones.
(x) Schiff’s base:
Schiff’s base is a substance compound that contains a twofold connection between carbon-nitrogen and the nitrogen iota associated with an aryl or alkyl bunch however, not hydrogen. They have the overall R1R2C formula= NR3. Subsequently, it’s an imine. It’s named for Hugo Schiff, a researcher.
NCERT Answers for Class 12 Science Part 12 Aldehydes, Ketones and Carboxylic Acids Q 12.1(x)
Aldehydes and ketones within the sight of a buildup of corrosive on treatment with essential aliphatic or fragrant amines yield a base of a Schiff.
Question 12.2: Name the following compounds according to the IUPAC system of nomenclature:
(i) CH3CH(CH3)CH2CH2CHO
(ii) CH3CH2COCH(C2H5)CH2CH2Cl
(iii) CH3CH=CHCHO
(iv) CH3COCH2COCH3
(v) CH3CH(CH3)CH2C(CH3)2COCH3
(vi) (CH3)3CCH2COOH
(vii) OHCC6H4CHO-p
Solution:
(i) 4-methylpentanal
(ii) 6-Chloro-4-ethylhexan-3-one
(iii) But-2-en-1-al
(iv) Pentane-2,4-dione
(v) 3,3,5-Trimethylhexan-2-one
(vi) 3,3-Dimethylbutanoic acid
(vii) Benzene-1,4-dicarbaldehyde
Question 12.4: Write the IUPAC names of the following ketones and aldehydes. Wherever
possible, also give common names.
(i) CH3CO(CH2)4CH3
(ii) CH3CH2CHBrCH2CH(CH3)CHO
(iii) CH3(CH2)5CHO
(iv)Ph-CH=CH-CHO
(v)NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids Q 12.4(v)
(vi)PhCOPh
Solution:
(i) CH3CO(CH2)4CH3
IUPAC name: Heptan-2-one
Common name: Methyl pentyl ketone
(ii) CH3CH2CHBrCH2CH(CH3)CHO
IUPAC name: 4-Bromo-2-methylhaxanal
Common name: (γ-Bromo-α-methyl-caproaldehyde)
(iii) CH3(CH2)5CHO
IUPAC name: Heptanal
(iv) Ph-CH=CH-CHO
IUPAC name: 3-phenylprop-2-enal
Common name: β-Pheynolacrolein
(v)NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids Q 12.4(v)
IUPAC name: Cyclopentanecarbaldehyde
(vi) PhCOPh
IUPAC name: Diphenylmethanone
Common name: Benzophenone
Question 12.7: 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.
(i) Methanal
(ii) 2-Methylpentanal
(iii) Benzaldehyde
(iv) Benzophenone
(v) Cyclohexanone
(vi) 1-Phenylpropanone
(vii) Phenylacetaldehyde
(viii) Butan-1-ol
(ix) 2, 2-Dimethylbutanal
Solution:
Aldehydes and ketones having at least one α-hydrogen undergo aldol condensation. The compounds (ii) 2−methylpentanal, (v) cyclohexanone, (vi) 1-phenylpropanone, and (vii) phenylacetaldehyde contain one or more α-hydrogen atoms. Therefore, these undergo aldol condensation.
Aldehydes having no α-hydrogen atoms undergo Cannizzaro reactions. The compounds (i) Methanal, (iii) Benzaldehyde, and (ix) 2, 2-dimethylbutanal do not have any αhydrogen.
Therefore, these undergo Cannizzaro reactions.
Compound (iv) Benzophenone is a ketone having no α-hydrogen atom, and compound (viii) Butan-1-ol is alcohol. Hence, these compounds do not undergo either aldol condensation or Cannizzaro reactions.