Aldehydes Ketones and Carboxylic Acids HOTs Class 12 Chemistry

Please refer to Aldehydes Ketones and Carboxylic Acids HOTs Class 12 Chemistry provided below with solutions. All HOTs for Class 12 Chemistry with answers provided below have been designed as per the latest syllabus and examination petter issued by CBSE, NCERT, KVS. Students of Standard 12 Chemistry should learn the solved HOTS for Class 12 Chemistry provided below to gain better marks in examinations.

Aldehydes Ketones and Carboxylic Acids Class 12 Chemistry HOTs

Question. Vinegar is a solution of acetic acid which is :
(a) 15 – 20%
(b) 20 –25%
(c) 6 – 8%
(d) 2 – 4%

Question. The correct order of increasing acidic strength is__________
(a) Phenol < Ethanol < Chloroacetic acid < Acetic acid
(b) Ethanol < Phenol < Chloroacetic acid < Acetic acid
(c) Ethanol < Phenol < Acetic acid < Chloroacetic acid
(d) Chloroacetic acid < Acetic acid < Phenol < Ethanol

Question. Methyl cyanide can be converted into acetic acid by one of the following reactions.
(a) Reduction
(b) Hydrolysis
(c) Electrolysis
(d) Decarboxylation

Question. The product obtained by the reaction of an aldehyde and hydroxylamine is
(a) hydrazone
(b) aldoxime
(c) primary amine
(d) alcohol

Question. Which one gives positive iodoform test ?

Question. Which one of the following esters is obtained by the esterification of propan-2-ol with ethanoic acid ?
(a) (CH₃)₂CHCOOCH₃
(b) CH₃COOCH₂CH₃
(c) CH₃COOCH(CH₃)₂
(d) (CH₃)₂CHCOOCH₂CH₃

Question. Schiff’s reagent gives pink colour with
(a) acetaldehyde
(b) acetone
(c) acetic acid
(d) methyl acetate

Question. The yield of ester in esterification can be increased by
CH₃CH₂OH + CH₃COOH ⇌ CH₃COOCH₂CH₃ + H ₂O
(a) removing water
(b) taking ethanol in excess
(c) taking acetic acid in excess
(d) all the above factors

Question. Which of the following has the maximum acidic strength ?
(a) o- nitrobenzoic acid
(b) m-nitrobenzoic acid
(c) p-nitrobenzoic acid
(d) p-nitrophenol

Question. In the reaction of NaHSO₃ with carbonyl compounds to form bisulphite product, the nucleophile is
(a) HSO₃^–
(b) SO₃Na
(c) SO₃^{– –}
(d) None of the above

Question. Tollen’s reagent is
(a) ammonical CuSO₄
(b) ammonical AgNO₃
(c) alkaline solution containing complex of copper nitrate
(d) none of these

Question. Which of the following is the correct decreasing order of acidic strength of
(i) Methanoic acid (ii) Ethanoic acid
(iii) Propanoic acid (iv) Butanoic acid
(a) (i) > (ii) > (iii) > (iv)
(b) (ii) > (iii) > (iv) > (i)
(c) (i) > (iv) > (iii) > (ii)
(d) (iv) > (i) > (iii) > (ii)

Question. The reaction

is called as
(a) Reimer- Tiemann reaction
(b) Hell-Volhard Zelinsky reaction
(c) Cannizzaro reaction
(d) Sandmeyer reaction

Question. Among the following the strongest acid is
(a) CH₃COOH
(b) CH₂ClCH₂COOH
(c) CH₂ClCOOH
(d) CH₃CH₂COOH

Question. Compound of general formula

(a) diester
(b ) acid anhydride
(c) hemiacetal
(d) acetal

Question. In the following reaction

The major compounds X and Y are
(a) RCHBrCONH₂ ; RCH(NH₂)COOH
(b) RCHBrCOOH ; RCH(NH₂)COOH
(c) RCH₂COBr ; RCH₂COONH₄
(d) RCHBrCOOH ; RCH₂CONH₂

Question. Benzoic acid may be converted to ethyl benzoate by reaction with
(a) sodium ethoxide
(b) ethyl chloride
(c) dry HCl—C₂H₅OH
(d) ethanol

Question. The difference between aldol condensation and Cannizzaro’s reaction is that:
(a) the former takes place in the presence of α-H-atom.
(b) the former takes place in the absence of α-H-atom.
(c) the former takes place in the presence of β-H-atom.
(d) none of the above

Question. The product obtained when acetic acid is treated with phosphorus trichloride is
(a) CH₃COOPCl₃
(b) ClCH₂COCl
(c) CH₃COCl
(d) ClCH₂COOH

Question. Which of the following pairs of compounds will undergo aldol and Cannizzaro reaction respectively ?
(i) acetone; benzaldehyde
(ii) acetaldehyde; butan–2–one
(iii) propanone; formaldehyde.
(iv) cyclopentanone, benzaldehyde
(a) (i), (ii) and (iii)
(b) (ii) and (iii)
(c) (ii), (iii) and (iv)
(d) (iii) and (iv)

Question. The compound that neither forms semicarbazone nor oxime is
(a) HCHO
(b) CH₃COCH₂Cl
(c) CH₃CHO
(d) CH₃CONHCH₃

Question. The reagent which does not react with both, acetone and benzaldehyde.
(a) Sodium hydrogensulphite
(b) Phenyl hydrazine
(c) Fehling’s solution
(d) Grignard reagent

Question. A and B in the following reactions are

Question. Which of the following does not represent the natural source of the corresponding acids ?
(a) Formic acid : Red ant
(b) Acetic acid : Vinegar
(c) Butyric acid : Rancid butter
(d) Isobutyric acid : Automobile exhausts

Question. Arrange the following carboxylic acid in their decreasing acidity.

(a) 3 > 2 > 1
(b) 1 > 2 > 3
(c) 2 > 3 > 1
(d) 2 > 1 > 3

Question. Which reagent can convert acetic acid into ethanol ?
(a) Na + alcohol
(b) LiAIH₄ + ether
(c) H₂ + Pt
(d) Sn + HCl

Question. Which of the following does the best represent the structure of the carboxylate ion ?

Question. Which of the following products is formed when benzaldehyde is treated with CH₃MgBr and the addition product so obtained is subjected to acid hydrolysis ?
(a) A secondary alcohol
(b) A primary alcohol
(c) Phenol
(d) tert-Butyl alcohol

Question. Benzophenone can be converted into benzene by using
(a) fused alkali
(b) anhydrous AlCl₃
(c) sodium amalgam in water
(d) acidified dichromate

Question. In the given reaction

Question. Imine derivatives of aldehyde and ketone is called as
(a) Schiff’s reagent
(b) Fehling’s reagent
(c) Schiff’s base
(d) Schiff’s acid

Question. Which of the following compounds is most reactive towards nucleophilic addition reactions?

Question. Which of the following can not be oxidised to give carboxylic acid?

Question.

In the above sequence X can be :
(a) H₂ /Ni
(b) NaBH₄
(c) K₂Cr₂O₇/H⁺
(d) Both (a) and (b)

MATCHING TYPE QUESTIONS

Question. Match the columns
Column-I                                 Column-II
(Reactions) (Reagents)
(A) Benzophenone →                (p) LiAlH₄
Diphenylmethane
(B) Benzaldehyde →                 (q) DIBAL–H
1-Phenylethanol
(C) Cyclohexanone →               (r) Zn(Hg)/Conc HCl
Cyclohexanol
(D) Phenyl benzoate →             (s) CH₃MgBr
Benzaldehyde
(a) A – (p), B – (s), C – (r), D – (q)
(b) A – (q), B – (s), C – (p), D – (r)
(c) A – (s), B – (r), C – (q), D – (p)
(d) A – (r), B – (s), C – (p), D – (q)

Question.Match the columns

(a) A – (q), B – (p), C – (s), D – (r)
(b) A – (r), B – (p), C – (s), D – (q)
(c) A – (s), B – (r), C – (p), D – (q)
(d) A – (r), B – (q), C – (s), D – (p)

Question. Match the columns

(a) A – (p), B – (q), C – (r), D – (s)
(b) A – (q), B – (p), C – (r), D – (s)
(c) A – (r), B – (s), C – (p), D – (q)
(d) A – (s), B – (r), C – (p), D – (q)

Question. Match the columns
Column-I                                              Column-II
(A) Etard reaction                               (p) Alcoholic KOH
(B) Hydroxylation                               (q) Anhydrous AlCl₃
(C) Dehydrohalogenation                     (r) Chromyl chloride
(D) Friedel-Crafts reaction                   (s) Dilute alkaline KMnO₄
(a) A – (p), B – (q), C – (r), D – (q)
(b) A – (s), B – (r), C – (p), D – (q)
(c) A – (r), B – (s), C – (p), D – (q)
(d) A – (q), B – (p), C – (s), D – (r)

Question. Match the columns
Column-I Column-II
(Common names)                      (IUPAC names)
(A) Cinnamaldehyde                  (p) Pentanal
(B) Acetophenone                     (q) Prop-2-enal
(C) Valeraldehyde                     (r) 4-Methylpent-3-en-2-one
(D) Acrolein                              (s) 3-Phenylprop-2-enal
(E) Mesityl oxide (t) 1-Phenylethanone
(a) A – (s), B – (t), C – (p), D – (q), E – (r)
(b) A – (p), B – (q), C – (s), D – (t), E – (r)
(c) A – (t), B – (s), C – (p), D – (r), E – (q)
(d) A – (q), B – (t), C – (r), D – (s), E – (p)

Question. Match the acids given in Column-I with their correct IUPAC names given in Column-II.
Column-I                                   Column-II
(Acids)                                     (IUPAC names)
(A) Phthalic acid                    (p) Hexane-1, 6-dioic acid
(B) Oxalic acid                      (q) Benzene-1, 2-dicarboxylic acid
(C) Succinic acid                  (r) Pentane-1, 5-dioic acid
(D) Adipic acid                     (s) Butane-1, 4-dioic acid
(E) Glutaric acid                   (t) Ethane-1, 2-dioic acid
(a) A – (t), B – (q), C – (r), D – (p), E – (s)
(b) A – (p), B – (s), C – (t), D – (q), E – (r)
(c) A – (q), B – (t), C – (s), D – (p), E – (r)
(d) A – (r), B – (t), C – (p), D – (s), E – (q)

Question Match the columns

(a) A – (q), B – (s), C – (p), D – (r)
(b) A – (r), B – (p), C– (s), D– (q)
(c) A – (r), B – (s), C – (p), D– (q)
(d) A – (s), B – (r), C – (q), D– (p)

ASSERTION-REASON TYPE QUESTIONS

Directions : Each of these questions contain two statements,Assertion and Reason. Each of these questions also has four alternative choices, only one of which is the correct answer. You have to select one of the codes (a), (b), (c) and (d) given below.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Question. Assertion : Formaldehyde is a planar molecule.
Reason : It contains sp² hybridised carbon atom.

Question. Assertion : The boiling points of aldehydes and ketones are higher than hydrocarbons and ethers of comparable molecular masses.
Reason : There is a weak molecular association in aldehydes and ketones arising out of the dipole-dipole interactions.

Question. Assertion : The molecular mass of acetic acid in benzene is 120 instead of 60.
Reason : The carboxylic acids exist as cyclic dimers in which the two molecules of the acid are held together by two strong hydrogen bonds.

Question. Assertion : Compounds containing –CHO group are easily oxidised to corresponding carboxylic acids.
Reason : Carboxylic acids can be reduced to alcohols by treatment with LiAlH₄.

VERY SHORT ANSWER TYPE QUESTIONS (1 MARK)

Question. Arrange the following compounds in an increasing order of their reactivity towards nucleophilic addition reaction.
CH₃CHO, CH₃CH₂CHO ,CH₃COCH₃,CH₃COCH₂CH₃.
Answer. CH₃COCH₂CH₃< CH₃COCH₃< CH₃CH₂CHO < CH₃CHO

Question. Name the reagent which is used to convert allyl alcohol to propanol.
Answer. PCC (Pyridinium Chlorochromate)

Question. Name the aldehyde which does not give Fehling solution test.
Answer. Benzaldehyde.

Question. Write IUPAC name of the compound CH₂ = CHCOCH₂COOH
Answer. 3‐Oxopent‐4‐ enoic acid

Question. Complete the reaction:

Answer.

SHORT ANSWER TYPE QUESTIONS 

Question. Arrange the following.
(i) C₆H₅COOH, FCH₂COOH, NO₂CH₂COOH( decreasing order of their acidic character)
(ii) Ethanal, Propanal, Propanone, Butanone reaction (increasing order of their nucleophilic addition reaction)
Answer. (i) NO₂‐CH₂‐COOH> F‐CH₂‐COOH >C₆H₅‐COOH
(ii) Butanone < Propanone < Propanal < Ethanal

Question. Give a chemical test to distinguish between the following pairs:‐
(i) Phenol and benzoic acid
(ii) Benzaldehyde and Acetophenone
Answer. (i) Benzoic acid reacts with NaHCO₃ giving CO₂ gas with effervescence where as phenol does not.

(ii) Acetophenone on reacting with hot NaOH / I₂ gives yellow ppt of CHI₃ while

Question. Write chemical equation to illustrate following name reactions:‐
(a) Cannizzaro’s reaction
(b) Hell‐Volhard‐ Zelinsky reaction
Answer. (a) Cannizzaro’s reaction

Question. An organic compound ‘A’ with molecular formula C8H8O gives positive DNP and iododorm test. It does not reduce Tollens’ or Fehling’s reagent and does not decolourise bromine water also . On oxidation with chromic acid, it gives a carboxylic acid ‘B’ with molecular formula C₇H₆O₂. Deduce the structures A and B.
Answer. Since A does not give Fehling’s or Tollen‘s test but gives iodoform test and 2,4‐ DNP test so it has CH₃ CO‐ group. Hence:

Question. Account for the following :‐
(i) Chloroacetic acid Cl‐CH₂COOH is a stronger acid than acetic acid CH₃COOH.
(ii) Carboxylic acids do not give the reaction of carbonyl group.
Answer. (i) The –I effect of Cl atom in ClCH₂ COOH stabiles the ClCH COO ion while +I e ffect of CH ‐ group in CH₃ COOH destabilizes the CH₃COO .
(ii) In the resonating structures of carboxylic acid and carbonyls, the carbonyl carbon of carboxylic acid is less electro‐positive (less electrophile) than carbonyl carbon in aldehydes and ketones. Therefore carboxylic acids do not give the reaction of carbonyl group

SHORT ANSWER TYPE QUESTIONS

Question.1. Explain the following name reaction by giving one suitable example of each:‐
(i) Wolff‐kishner reduction (ii) Aldol condensation (iii) Clemensen’s reduction
Answer. (i) Wolff‐kishner reduction

Carbonyl compounds with α‐ hydrogen in basic medium undergo condensation to give Hydroxy aldehydes and ketones.

(iii) Clemensen’s reduction

Question. Explain : (i) Ethanal is more reactive than acetophenone towards nucleophilic addition reaction.
(ii)(CH₃)₃C‐CHO does not undergo aldol condensation.
(iii)Carboxylic acids are higher boiling liquids than alcohols.
Answer. (i) The presence of two alkyl groups in ketones hinder the approach of nucleophile to carbonyl carbon,and reduce the positive charge on carbonyl carbon more effectively in ketones than in aldehydes.
(i) Due to unavailability of α‐hydrogen in the given compound it does not undergo aldol condensation.
(ii) Due to extensive association of carboxylic acid molecules through intermolecular hydrogen bonding,(exist as dimer)

Question.
Write the products in the following reactions:

Answer.

LONG ANSWER TYPE QUESTIONS 

Question.

Answer. A- Benzoyl chloride B- Benzaldehyde
C – Benzylalcohol
D – Sodium benzoate

(b) Distinguish between: (i) Acetone and Acetaldehyde (ii) Benzaldehyde and Benzophenone
Answer. (iii) Bezaldehyde gives Tollens’ test, while benzophenonedoes not.
C₆H₅CHO + 2[Ag(NH₃)₂] → C₆H₅COONH4 +2Ag + 3NH₃ +H₂O

Question. (a) Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol. Give two reasons.
(b) How will you bring about the following conversions?
(i) Acetic acid to Acetaldehyde
(ii) Propylene to Acetone
(iii) Ethanal to but‐2‐enal
Answer. (a) (i) resonating structures of carboxylate ion are more stable than phenoxide ion.
(ii) Negative charge is dispersing on two electronegative oxygen in carboxylate ion whereas in phenoxide ion it is on one oxygen.