VBQs Aldehydes Ketones and Carboxylic Acids 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. Less reactivity of ketone is due to
(a) + I inductive effect decrease positive charge on carbonyl carbon atom
(b) steric effect of two bulky alkyl groups
(c) sp² hybridised carbon atom of carbonyl carbon atom
(d) Both (a) and (b)

Question. Which one of the following can be oxidised to the corresponding carbonyl compound?
(a) 2-hydroxy-propane
(b) Ortho-nitrophenol
(c) Phenol
(d) 2-methyl-2 hydroxy-propane

Question. Which one of the following on oxidation gives a ketone ?
(a) Primary alcohol
(b) Secondary alcohol
(c) Tertiary alcohol
(d) All of these

Question. Carbonyl compounds undergo nucleophilic addition because of
(a) electronegativity difference of carbon and oxygen atoms
(b) electromeric effect
(c) more stable anion with negative charge on oxygen atom and less stable carbonium ion
(d) None of the above

Question. Clemmensen reduction of a ketone is carried out in the presence of which of the following ?
(a) Glycol with KOH
(b) Zn-Hg with HCl
(c) LiAlH₄
(d) H₂ and Pt as catalyst

Question. If formaldehyde and KOH are heated, then we get
(a) methane
(b) methyl alcohol
(c) ethyl formate
(d) acetylene

Question. Benzaldehyde reacts with ethanoic KCN to give
(a) C₆H₅CHOHCN
(b) C₆H₅CHOHCOC₆H₅
(c) C₆H₅CHOHCOOH
(d) C₆H₅CHOHCHOHC₆H₅

Question. The reagent which can be used to distinguish acetophenone from benzophenone is
(a) 2,4- dinitrophenylhydrazine
(b) aqueous solution of NaHSO₃
(c) benedict reagent
(d) I₂and Na₂CO₃

Question. Choose the correct IUPAC name for

(a) Butan – 2- aldehyde
(b) 2- methylbutanal
(c) 3- methylisobutyraldehyde
(d) 2- ethylpropanal

Question. The IUPAC name of the compound having the molecular formula Cl₃C –CH₂CHO is
(a) 3, 3, 3- trichloropropanal
(b) 1, 1, 1- trichloropropanal
(c) 2, 2, 2- trichloropropanal
(d) Chloral

Question. Acetaldehyde reacts with semicarbazide and forms semicarbazone. Its structure is

Question.

The above reaction is
(a) Mendius reaction
(b) Sandorn’s reaction
(c) Rosenmund’s reaction
(d) Stephen’s reaction

Question. Phenylmethyl ketone can be converted into ethylbenzene in one step by which of the following reagents?
(a) LiAlH₄
(b) Zn-Hg/HCl
(c) NaBH₄
(d) CH₃MgI

Question. What is formed when a primary alcohol undergoes catalytic dehydrogenation ?
(a) Aldehyde
(b) Ketone
(c) Alkene
(d) Acid

Question. Aldol condensation would not occur in :
(a) CH₃COCH₃
(b) CH₃CH₂CHO
(c) HCHO
(d) CH₃CHO

Question. The catalyst used in Rosenmund’s reduction is
(a) HgSO₄
(b) Pd/BaSO₄
(c) anhydrous AlCl₃
(d) anhydrous ZnCl₂

Question. Which of the following is used to prepare ketone from acyl chloride ?
(a) R-MgX
(b) R₂Cd
(c) CO + HCl
(d) CrO₃

Question. Aldehydes and ketones are distinguished by which of the following test ?
(a) Lucas test
(b) Tollen’s test
(c) KMnO₄ solution (Baeyer’s test)
(d) None of these

Question. The oxidation of toluene to benzaldehyde by chromyl chloride is called
(a) Rosenmund reaction
(b) Wurtz reaction
(c) Etard reaction
(d) Fittig reaction

Question. A compound does not react with 2, 4-dinitrophenylhydrazine, the compound is :
(a) Acetone
(b) Acetaldehdye
(c) CH₃OH
(d) CH₃CH₂COCH₃

Question. Propanal and propanone, both have same molecular formula(C₃H₆O), what do you expect about their boiling points?
(a) Both have same boiling point
(b) Boiling point of propanal is higher than the boiling point of propanone.
(c) Boiling point of propanal is lower than the boiling point of propanone
(d) Nothing can be predicted

Question. The most appropriate reagent to distinguish between acetaldehyde and formaldehyde is :
(a) Fehling’s solution
(b) Tollen’s reagent
(c) Schiff’s reagent
(d) Iodine in presence of base

Question. Which of the following contain an aldehyde?
(a) Vanilla beans
(b) Meadow sweet
(c) Cinnamon
(d) All of these

Question. 2-pentanone and 3-pentanone can be distinguished by :
(a) Cannizaro’s reaction
(b) Aldol condensation
(c) Iodoform reaction
(d) Clemmensen’s reduction

Question.Which of the following statement is false ?
(a) Cannizzaro reaction is given by aldehydes in presence of alkali
(b) Aldol condensation is given by aldehydes in presence of alkali
(c) Aldol condensation is given by aldehydes and ketones in presence of acids
(d) None of the above

Question. Iodoform test is not given by
(a) 2-Pentanone
(b) Ethanol
(c) Ethanal
(d) 3-Pentanone

Question. Ketone upon treatment with Grignard Reagent gives
(a) primary alcohol
(b) secondary alcohol
(c) tertiary alcohol
(d) aldehyde

Question. Which of the following have pleasant smell?
(a) Methanal
(b) Propanal
(c) Ethanal
(d) Hexanal

Question.The product formed in Aldol condensation is
(a) a beta-hydroxy aldehyde or a beta-hydroxy ketone
(b) an alpha-hydroxy aldehyde or ketone
(c) an alpha, beta unsaturated ester
(d) a beta-hydroxy acid

Question. Product of the following reaction is

CRITICAL THINKING TYPE QUESTIONS

Question. Aldehydes and ketones will not form crystalline derivatives with
(a) sodium bisulphite
(b) phenylhydrazine
(c) semicarbazide hydrochloride
(d) dihydrogen sodium phosphate.

Question. Observe the following structures and pick up the correct statement.

(a) Carbonyl carbon of I is more electrophilic than that of II
(b) Carbonyl carbon of I is less electrophilic than that of II
(c) Carbonyl carbon of both structures have equal electrophilic character
(d) It depends upon the complete structure of the compound

Question. In a set of the given reactions, acetic acid yielded a product C.

Question. Which of the following acts as a nucleophile in the aldol condensation of ethanal?

(a) Only (i)
(b) (i) and (ii)
(c) (i) and (iii)
(d) All the three

Question. Product of the following reaction is

Question.

Compound (C) in above reaction is
(a) α-hydroxy acid
(b) α-amino acid
(c) α-amino alkanol
(d) α-amino β-hydroxy acid

Question. Which of the following represents the correct order of the acidity in the given compounds?
(a) FCH₂COOH > CH₃COOH > BrCH₂COOH > ClCH₂COOH
(b) BrCH₂COOH > ClCH₂COOH > FCH₂COOH > CH₃COOH
(c) FCH₂COOH > ClCH₂COOH > BrCH₂COOH > CH₃COOH
(d) CH₃ COOH > BrCH₂COOH > ClCH₂COOH > FCH₂COOH

Question. Ethanoic acid can’t be obtained by which of the following reaction ?

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

Question. In the crossed Cannizzaro reaction involving HCHO as one of the components
(a) HCHO is always oxidised because of electronic effect
(b) HCHO is always oxidised because of steric effect
(c) both of the above statements are true
(d) none of the above statement is true

Question. The end product B in the sequence of reactions,

(a) an alkane
(b) a carboxylic acid
(c) sodium salt of carboxylic acid
(d) a ketone

Question. When ethanal reacts with propanal in the presence of a base, the number of products formed is
(a) 2
(b) 3
(c) 4
(d) 5

Question. Suppose the reaction of compound containing ketone as functional group is carried in basic medium of NaOH. Which of the following will one use to protect the unwanted reaction due presence of carbonyl moiety.
(a) NaHSO₃
(b) HCN
(c) ethylene glycol and HCl
(d) None of these

Question. Which of the following compound will undergo self aldol condensation in the presence of cold dilute alkali ?
(a) CH₂=CH—CHO
(b) CH≡C—CHO
(c) C₆H5CHO
(d) CH₃CH₂CHO.

Question. IUPAC name of the following compound is

(a) 2-(2-propenyl) butanal
(b) 2-(1-propenyl) butanal
(c) 4-formyl 4-ethyl but-2-ene
(d) 2-ethyl pent-3-en-l-al

Question. Which of the following reagent reacts in different ways with CH₃CHO, HCHO and C₆H₅CHO ?
(a) Fehling solution
(b) C₆H₅NHNH₂
(c) Ammonia
(d) HCl

Question. An organic compound of formula, C₃H₆O forms phenyl hydrazone, but gives negative Tollen’s test. The compound is
(a) CH₃CH₂COCH₃
(b) CH₃CH₂CHO
(c) CH₃COCH₃
(d) Both (a) and (c)

Question. Cannizaro’s reaction is not given by _____________

Question. The boiling points of aldehydes and ketones lie in between alkanes and alcohols of comparable masses because
(a) alkanes are polar
(b) aldehydes and ketones are non-polar
(c) alkanes are non-polar and aldehydes and ketones contain polar

group and lower alcohols have H-bonding.
(d) alkanes are held together by weak van der Waal’s forces (being non-polar), aldehydes and ketones contain polar

group and held together by strong dipole-dipole attraction and lower alcohols have H-bonding, which is stronger than dipole-dipole attraction.

Question. Which of the following is correct order of acidity?
(a) HCOOH > CH₃COOH > ClCH₂COOH > C₂H₅ COOH
(b) ClCH₂COOH > HCOOH > CH₃COOH > C₂H₅COOH
(c) CH₃COOH > HCOOH > ClCH₂COOH > C₂H₅COOH
(d) C₂H5COOH > CH₃COOH > HCOOH > ClCH₂COOH

Question.

Question. An organic compound A upon reacting with NH₃ gives B.
On heating B gives C. C in presence of KOH reacts with Br₂ to given CH₃CH₂NH₂. A is :

Question. A compound C₅H₁₀O forms orange–red precipitate upon reaction with 2,4–DNP, but does not give positive Tollen’s test and iodoform test. Possible compound is
(a) 2, 2–dimethylpropanal
(b) 3–methylbutan–2–one
(c) Pentan–3–one
(d) None of the above

Question. The correct order for the acidic character of the following carboxylic acids is

(a) IV > I > II > III > V
(b) V > II > III > I > IV
(c) V > II > IV > III > I
(d) V > II > IV > I > III