Aldehydes Ketones and Carboxylic Acids VBQs Class 12 Chemistry

VBQs Aldehydes Ketones and Carboxylic Acids Class 12 Chemistry with Aldehydes Ketones and Carboxylic Acids has been provided below for standard students. We have provided chapter wise VBQ for Class 12 Chemistry with Aldehydes Ketones and Carboxylic Acids. The following Aldehydes Ketones and Carboxylic Acids Class 12 Chemistry value based questions with answers will come in your exams. Students should understand the concepts and learn the solved cased based VBQs provided below. This will help you to get better marks in class 12 examinations.

Aldehydes Ketones and Carboxylic Acids VBQs Class 12 Chemistry

Question. Benzaldehyde is obtained from Rosenmund’s reduction of

Question. The IUPAC name of CH₃COCH(CH₃)₂ is
(a) 2-methyl-3-butanone
(b) 4-methylisopropyl ketone
(c) 3-methyl-2-butanone
(d) Isopropylmethyl ketone

Question. Acetaldehyde reacts with
(a) Electrophiles only
(b) Nucleophiles only
(c) Free radicals only
(d) Both electrophiles and nucleophiles

Question. IUPAC name of ethyl isopropyl ketone is
(a) 4-methyl pent-3-one
(b) 2-methyl pent-3-one
(c) 4-methyl pent-2-one
(d) 2-methyl pent-2-one

Question. The reaction

(a) Rosenmund’s reaction
(b) Stephen’s reaction
(c) Cannizzaro’s reaction
(d) Gatterman-Koch reaction

Question. Acetone reacts with iodine (I₂) to form iodoform in the presence of
(a) CaCO₃
(b) NaOH
(c) KOH
(d) MgCO₃

Question. Aldehydes and ketones are generally reduced by :
(a) Clemmensen reduction
(b) H₂S
(c) H₂ / Ni
(d) None of these

Question. In which reaction, > C = O can be reduced to > CH₂?
(a) Wolf-Kishner reaction
(b) Reimer-Tiemann reaction
(c) Wurtz reaction
(d) None of these

Question. Which of the following is correct for carbonyl compounds?

Question. Cross aldol condensation occurs between
(a) two same aldehydes
(b) two same ketones
(c) two different aldehydes and ketones
(d) None of these

Question. Which gives lactic acid on hydrolysis after reacting with HCN ?
(a) HCHO
(b) CH₃CHO
(c) C₆H₅CHO
(d) CH₃COCH₃

Question. Primary and secondary alcohols on action of reduced copper give
(a) Aldehydes and ketones respectively
(b) Ketones and aldehydes respectively
(c) Only aldehydes
(d) Only ketones

Question. Which alkene on ozonolysis gives CH₃CH₂CHO and

Question. When acetaldehyde is heated with Fehling’s solution it gives a precipitate of
(a) Cu
(b) CuO
(c) Cu₂O
(d) Cu(OH)₂

Question. Benzaldehyde can be prepared by oxidation of toluene by
(a) Acidic KMnO₄
(b) K₂Cr₂O₇ / H⁺
(c) CrO₂Cl₂
(d) All of these

Question. Which is highly soluble in water?
(a) Methanal
(b) Propanal
(c) Propanone
(d) Butanone

Question. Cannizzaro reaction occurs with
(a) CH₃ — CH₂OH
(b) C₆H₅CHO
(c) CH₃CHO
(d) CH₃ — CO — CH₃

Question. An aldehyde group can be present
(a) in between carbon chain
(b) at any position in carbon atom
(c) only at the end of carbon chain
(d) at the second carbon atom of the carbon chain

Question. IUPAC name of following will be

(a) 4-formyl 3-methyl 1-hydroxy benzene
(b) 4-formyl 3-methyl phenol
(c) 4-hydroxy 2-methyl benzaldehyde
(d) 4-hydroxy 2-methyl carbaldehyde

Question. Which of the following is not used in the preparation of ketone?
(a) Oxidation of secondary alcohols
(b) Dehydrogenation of 2° alcohol
(c) Pyrolysis of calcium acetate
(d) Acid hydrolysis of alkyl cyanide

Question. In > C = O group sigma bond is formed by
(a) sp²-p-overlapping
(b) sp³-p-overlapping
(c) sp-p-overlapping
(d) s-p-overlapping

Question. Find out B in the given reactions

(a) acetophenone
(b) benzaldehyde
(c) cyclohexyl carbaldehyde
(d) benzoic acid

Question. When acetaldehyde reacts with alcohol then produce
(a) Acetal
(b) Ketal
(c) Acetone
(d) None

Question. Which of the following compound will show positive silver mirror test ?
(a) HCOOH
(b) CH₃(CHOH)₃CHO
(c) CH₃CO(CHOH)CH₃
(d) Both (a) and (b)

Question. Which aldehyde cannot be obtained by Rosenmund’s reaction?
(a) CH₃CHO
(b) HCHO
(c) CH₃CH₂CHO
(d) All of these

Question. The π-bond in carbonyl group is formed by
(a) s-s-overlapping
(b) p-p-overlapping
(c) s-p-overlapping
(d) p-d-overlapping

Question. The conversion PhCN → PhCOCH₃ , can be achieved most conveniently by reaction with
(a) CH₃MgBr followed by hydrolysis
(b) I₂ – NaOH, CH₃I
(c) Dil. H₂SO₄ followed by reaction with CH₂N₂
(d) LiAlH₄ followed by reaction with CH₃I

Question.Which of the following forces explain the boiling point of aldehydes and ketones?
(a) Hydrogen bonding
(b) van der Waal’s forces
(c) Dipole-dipole attraction
(d) None of these

Question. Aldehydes can be oxidised by :
(a) Tollen’s reagent
(b) Fehling solution
(c) Benedict solution
(d) All the above

Question. (CH₃)₃C–CHO does not undergo aldol condensation due to
(a) three electron donating methyl groups
(b) cleavage taking place between —C— CHO bond
(c) absence of alpha hydrogen atom in the molecule
(d) bulky (CH₃)₃C—group

CRITICAL THINKING TYPE QUESTIONS

Question. Which of the following is an example of nucleophilic addition ?

Question. A new carbon – carbon bond is formed in
(i) Aldol condensation
(ii) Kolbe’s reaction
(iii) Reimer-Tiemann reaction
(iv) Wurtz Fittig reaction
(a) (i) and (iii)
(b) (ii) and (iii)
(c) (i), (ii) and (iiv)
(d) All the four

Question. Which is the most suitable reagent for the following conversion?

(a) Tollen’s reagent
(b) Benzoyl peroxide
(c) I₂ and NaOH solution
(d) Sn and NaOH solution

Question. In the given reaction,

 Identify the product(s) formed in the given reaction.
           I                                        II
(a) 2 molecules of benzoic acid 2 molecules of ethanoic acid
(b) 2 molecules of benzoic acid 1 molecules of benzoic acid and 1 molecule of ethanoic acid
(c) 1 molecule of ethanoic acid 1 molecule of benzoic acid
(d) 1 molecule of benzoic acid 1 molecule of butanoic acid 

Question. Which of the following undergoes haloform reaction ?
(i) CH₃CH₂COCH₂Cl
(ii) C₆H₅COCH₃
(iii) C₆H₅COCHCl₂
(iv) CH₃CH₂COCCl₃
(a) Only (ii)
(b) (ii) and (iv)
(c) (i), (ii) and (iv)
(d) All the four

Question. Primary alcohols can be readily oxidised to carboxylic acids by.
(i) KMnO₄ in neutral medium.
(ii) KMnO₄ in acidic or alkaline medium.
(iii) K₂Cr₂O₇ in alkaline medium.
(iv) K₂Cr₂O₇ in acidic medium.
(a) (i), (ii) and (iv)
(b) (i), (ii) and (iii)
(c) (ii) and (iii)
(d) (i) and (iii)

Question. When benzaldehyde and acetaldehyde undergoes reaction with the 2, 4–DNP ?
(a) Benzaldehyde reacts slowly than acetaldehyde
(b) Acetaldehyde reacts slowly than benzaldehyde
(c) Both reacts equally
(d) Both do not react with 2, 4-DNP

Question. Which of the following is an example of aldol condensation?

Question. The correct order of increasing acid strength of the compounds

(a) D < A < B < C
(b) A < D < B < C
(c) B < D < A < C
(d) D < A < C < B

Question. Structure of the compound whose IUPAC name is 3-ethyl- 2-hydroxy-4-methylhex-3-en-5-ynoic acid is :

Question. RCOOH can be reduced to RCH₂OH by
(i) NaBH₄ (ii) LiAlH₄
(iii) Na/C₂H₅OH
(iv) H₂/Catalyst
(a) (ii) and (iv)
(b) (i) and (iii)
(c) (i), (ii) and (iv)
(d) (i), (iii) and (iv)

Question. Which of the following acts as a nucleophile in the Cannizzaro reaction involving benzaldehyde ?

(a) (i) and (iv)
(b) (i) and (ii)
(c) (i) and (iii)
(d) Only (i)

Question. Acetal formation is a reversible reaction

Under what conditions, the reaction can be forced to proceed only in right (forward) direction ?
(a) Using excess of alcohol
(b) Using high temperature
(c) Using dilute acid and excess of alcohol
(d) Using dry acid and excess of alcohol

Question. Nitration of the compound is carried out, this compound gives red–orange ppt. with 2,4–DNP, this compound undergoes Cannizzaro reaction but not aldol, than possible product due to nitration is
(a) 3–nitroacetophenone
(b) (2–nitro)–2–phenylethanal
(c) (2–nitro)–1–phenylpropan–2–one
(d) 3–nitrobezaldehyde

Question. Kolbe’s electrolytic method can be applied on

(iii) C₆H₅COOK (iv) CH₃COOK
(a) (i), (ii) and (iv)
(b) (i), (ii) and (iii)
(c) (ii), (iii) and (iv)
(d) (iii) and (iv)

Question. Identify X,

(a) CH₃OH
(b) Ethyl alcohol
(c) Methyl cyanide
(d) tert-Butyl alcohol

Question. Benzaldehyde is less reactive than propanal because
(i) the carbon atom of the carbonyl group of benzaldehyde is less electrophilic as in propanal.
(ii) the carbon atom of the carbonyl group of benzaldehyde is more electrophilic as in propanal.
(iii) carbonyl group in benzaldehyde is more polar due to resonance
(iv) carbonyl group in benzaldehyde is less polar due to resonance
(a) (i) and (iii)
(b) (i) and (iv)
(c) (i) only
(d) (iv) only

Question. Addition of alcohols to aldehydes and ketones takes place in presence of dry HCl gas because it
(i) Protonates the oxygen of the carbonyl compounds
(ii) Increases the electrophilicity of the carbonyl carbon
(iii) Removes the excess moisture from the reaction
(iv) Helps the reaction to move in the forward direction
(a) (i), (ii) and (iv)
(b) (i), (ii), (iii) and (iv)
(c) (ii) ,(iii), and (iv)
(d) (i), (iii) and (iv)

Question. Through which of the following reactions number of carbon atoms can be increased in the chain?
(i) Grignard reaction
(ii) Cannizzaro’s reaction
(iii) Aldol condensation
(iv) HVZ reaction
Choose the correct option.
(a) Only (iii) and (i)
(b) Only (iii) and (ii)
(c) Only (iii) and (iv)
(d) (i), (ii), (iii) and (iv)

Question. Which of the following conversions can be carried out by Clemmensen Reduction ?
(i) Benzaldehyde into benzyl alcohol
(ii) Cyclohexanone into cyclohexane
(iii) Benzoyl chloride into benzaldehyde
(iv) Benzophenone into diphenyl methane
(a) (ii) and (iv)
(b) (i) and (iv)
(c) (i) and (iii)
(d) (iii) and (iv)

Question. Addition of hydrogen cyanide to aldehydes and ketones occurs in presence of a base.The role of base is to
(i) catalyse the reaction
(ii) generate CN– ion
(iii) slow down the reaction
(iv) to stabilize the cyanohydrins
(a) (i) and (iii)
(b) (i) and (ii)
(c) (i) and (iv)
(d) (ii) and (iv)

Question. Benzophenone can be obtained by_____________.
(i) Benzoyl chloride + Benzene + AlCl₃
(ii) Benzoyl chloride + Diphenyl cadmium
(iii) Benzoyl chloride + Phenyl magnesium chloride
(iv) Benzene + Carbon monoxide + ZnCl₂
(a) (i), (ii) and (iii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i), (ii) and (iv)

SHORT ANSWER QUESTIONS (1-MARK)

Question. Why do carboxylic acids not give the characteristic reactions of a carbonyl group?
Answer. Due to resonance, It does not have free carbonyl.

Question. Aromatic acids are solid while most of aliphatic acids are liquids. Why?
Answer. Aromatic acids have higher molecular weight and strong Van der Waals force of attraction as compared to aliphatic acids so they are solids.

Question. Why is the boiling point of an acid anhydride higher than the acid from which it is derived?
Answer. Acid anhydrides are bigger in size than corresponding acid. These have more surface area so have strong van der Waals Force of attractions. Hence they have higher boiling point.

Question. The boiling points of aldehydes and ketones are lower than that of the corresponding acids. Why?
Answer. This is due to intermolecular hydrogen bonding in carboxylic acids.

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

Question. Why carboxylic acid have higher boiling point than alcohols as both have intermolecular hydrogen bonding?
Answer. Carboxylic acid forms a dimer due to double H-bonding. So it has higher boiling point than alcohols.

Question. What happens when ethanoyl chloride is subjected to rosenmund reduction?
Answer. Ethanoyl chloride is converted in to Ethanal. OR
CH₃COCl + H₂ Pd-BaSO₄/S CH₃CHO + HCl

Question. Arrange the following in increasing order of acidic character : HCOOH, CH₂ClCOOH ,CF₃COOH , CCl₃COOH
Answer. HCOOH < CH₂ClCOOH < CCl₃COOH < CF₃COOH

Question. Why PCC cannot oxidize methanol to methanoic acid while KMnO₄ can?
Answer. This is because PCC is a mild oxidizing agent and can oxidize methanol to methanal only.while KMnO₄ is strong oxidizing agent which oxidizes it to methanoic acid.

Question. Why does solubility decrease with increasing molecular mass in carboxylic acid?
Answer. Because with increase of molecular mass size of hydrophobic carbon chain length increases.