JEE Chemistry Aldehydes Ketones and Carboxylic Acids MCQs Set C

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)  (i) > (iv) > (iii) > (ii)
• c) (ii) > (iii) > (iv) > (i)
• d) (iv) > (i) > (iii) > (ii)

Answer: (i) > (ii) > (iii) > (iv)

Question: Among the following the strongest acid is

• a) CH₂ClCOOH
• b) CH₃COOH
• c) CH₃CH₂COOH
• d) None of these

Answer: CH₂ClCOOH

Question:

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

Answer: 1 > 2 > 3

Question: Read the following statements and choose the correct option

(i) The carbonyl carbon atom is sp² -hybridised
(ii) The carbonyl carbon is an electrophilic (Lewis acid) centre
(iii) The carbonyl oxygen is a nucleophilic (Lewis base) centre
(iv) Carbonyl compounds are non- polar in nature.

• a)  (i), (ii) and (iii) are correct
• b) (ii), (iii) and (iv) are correct
• c) (ii) and (iv) are correct
• d) (i), (ii) and (iv) are correct

Answer: (i), (ii) and (iii) are correct

Question: Which of the following statement(s) is/are true regarding preparation of aldehydes and ketones?

(i) Both can be prepared by the oxidation of the concerned alcohol with copper at about 250ºC.
(ii) Both can be prepared by the oxidation of the concerned alcohol by Oppenauer oxidation.
(iii) Both can be prepared by the oxidation of respective alcohol with acidic dichromate.

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

Answer: (i) only

Question: Which of the following statements are false?

(i) No aldehyde can be prepared by the oxidation of primary alcohol with acidic KMnO₄.
(ii) Aldehydes having a boiling point less than 100°C can be prepared by the oxidation of primary alcohol with acidic dichromate.
(iii) Secondary alcohols on oxidation with PCC in dichloromethane give carboxylic acids having lesser number of carbon atoms
(iv) Tertiary alcohols can't be oxidised at all

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

Answer: (i), (iii) and (iv)

Question: Read the following statements and choose the correct option

(i) The boiling points of aldehydes and ketones are lower than those of alcohols of similar molecular masses
(ii) Alcohols show intermolecular hydrogen bonding whereas aldehydes and ketones do not show intermolecular hydrogen bonding.
(iii) The lower members of aldehydes and ketones are miscible with water in all proportions, because they form hydrogen bond with water.
(iv) The solubility of aldehydes and ketones increases rapidly on increasing the length of alkyl chain.

• a) TTTF
• b) TFFT
• c) TTFF
• d) FTTT

Answer: TTTF

Question: Aldehydes are generally more reactive than ketones in nucleophilic addition reactions. Which of the following statements accounts for this ?

(i) Sterically, the presence of two relatively large substituents in ketones hinders the approach of nucleophile to carbonyl carbon
(ii) Aldehydes show resonance whereas ketones do not
(iii) Electronically, the presence of two alkyl groups reduce the electrophilicity of the carbonyl carbon more effectively.
(iv) Electronically carbonyl carbon atom in ketones is more electrophilic than in aldehydes

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

Answer: (i) and (iii)

Question:

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

Answer: (i) and (iv)

Question: Which of the following statement(s) is/are true regarding esterification of a carboxylic acid with an alcohol ?

(i) It is carried out in presence of a strong acid which acts as a catalyst.
(ii) The strong acid makes the carbonyl carbon more electrophilic, and hence causes the alcohol, a strong nucleophile to attack on the carbonyl carbon.
(iii) The strong acid makes the carbonyl group more electrophilic which is thus attacked easily by an alcohol, a weak nucleophile.
(iv) Esterification can be done even in absence of a strong acid.

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

Answer: (i) and (iii)

Question:

• 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)

Answer: A – (s), B – (t), C – (p), D – (q), E – (r)

Question:

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

Answer: A – (r), B – (s), C – (p), D – (q)

Question:

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

Answer: A – (s), B – (r), C – (p), D – (q)

Question:

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

Answer: A – (r), B – (s), C – (p), D – (q)

Question:

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

Answer: A – (r), B – (p), C– (s), D– (q)

Question:

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

Answer: A – (q), B – (t), C – (s), D – (p), E – (r)

Question:  Match the columns

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

Answer: A – (s), B – (r), C – (p), D – (q)

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.

• 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

Answer: Assertion is correct, reason is correct; reason is a correct explanation for assertion

Question: 

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

• 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

Answer: Assertion is correct, reason is correct; reason is a correct explanation for assertion

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.

• a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• b) Assertion is correct, reason is incorrect
• c) Assertion is incorrect, reason is correct
• d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: Assertion is correct, reason is correct; reason is not a correct explanation for assertion

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

• 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

Answer: Assertion is correct, reason is correct; reason is a correct explanation for assertion

Question:

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

Answer: 2-ethyl pent-3-en-l-al

Question:

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

Answer: Carbonyl carbon of I is less electrophilic than that of II

Question:  The boiling points of aldehydes and ketones lie in between alkanes and alcohols of comparable masses because

• a)

  

• b) aldehydes and ketones are non-polar
• c) alkanes are polar
• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which of the following reagent reacts in different ways with CH₃CHO, HCHO and C₆H₅CHO ?

• a) Ammonia
• b) Fehling solution
• c) HCl
• d) None of these

Answer: Ammonia

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) All the four
• b) (ii) and (iii)
• c) (i) and (iii)
• d) (i), (ii) and (iiv)

Answer: All the four

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

• a) Both
• b)

  

• c)

  

• d) None of these

Answer: Both

Question:

• a) Using dry acid and excess of alcohol
• b) Using dilute acid and excess of alcohol
• c) Using high temperature
• d) Using excess of alcohol

Answer: Using dry acid and excess of alcohol

Question: In the crossed Cannizzaro reaction involving HCHO as one of the components

• a) both of the above statements are true
• b) none of the above statement is true
• c) HCHO is always oxidised because of steric effect
• d) HCHO is always oxidised because of electronic effect

Answer: both of the above statements are true

Question:

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

Answer: (i) and (iii)

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

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

Answer: (i) and (iii)

Question:

• a) All the four
• b) (ii) and (iv)
• c) Only (ii)
• d) (i), (ii) and (iv)

Answer: All the four

Question: When ethanal reacts with propanal in the presence of a base, the number of products formed is

• a) 4
• b) 2
• c) 3
• d) 5

Answer: 4

Question: Aldehydes and ketones will not form crystalline derivatives with

• a) dihydrogen sodium phosphate
• b) semicarbazide hydrochloride
• c) phenylhydrazine
• d) sodium bisulphite

Answer: dihydrogen sodium phosphate

Question:  Which of the following compound will undergo self aldol condensation in the presence of cold dilute alkali ?

• a) CH₃CH₂CHO
• b) C₆H₅CHO
• c) Both
• d) None of these

Answer: CH₃CH₂CHO

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

• a)

  

• b)

  

• c)

  

• d) None of the above

Answer:

Question:

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

Answer: tert-Butyl alcohol

Question: An organic compound of formula, C₃H₆O forms phenyl hydrazone, but gives negative Tollen’s test. The compound is

• a) Both
• b) CH₃CH₂COCH₃
• c) CH₃COCH₃
• d) None of these

Answer:  Both

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Cannizaro’s reaction is not given by _____________

• a) CH₃CHO
• b) HCHO
• c)

  

• d)

  

Answer: CH₃CHO

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) (iii) and (iv)
• c) (ii) and (iii)
• d) (i), (ii) and (iv)

Answer: (i), (ii) and (iii)

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 (iii)
• c) (i) and (iv)
• d) (iii) and (iv)

Answer: (ii) and (iv)

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 (iv)
• b) (iv) only
• c) (i) and (iii)
• d) None of these

Answer: (i) and (iv)

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), (iii) and (iv)
• b) (i), (iii) and (iv)
• c) (i), (ii) and (iv)
• d) (ii) ,(iii), and (iv)

Answer: (i), (ii), (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 (ii)
• b) (ii) and (iv)
• c) (i) and (iii)
• d) (i) and (iv)

Answer: (i) and (ii)

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

Answer: Benzaldehyde reacts slowly than acetaldehyde

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) ethylene glycol and HCl
• b) HCN
• c) NaHSO₃
• d) None of these

Answer: ethylene glycol and HCl

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) Pentan–3–one
• b) 2, 2–dimethylpropanal
• c) 3–methylbutan–2–one
• d) None of the above

Answer: Pentan–3–one

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–nitrobezaldehyde
• b) None of these
• c) (2–nitro)–2–phenylethanal
• d) 3–nitroacetophenone

Answer:  3–nitrobezaldehyde

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

• a)

  

• b) Both
• c)

  

• d) None of these

Answer:

Question:

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

Answer: sodium salt of carboxylic acid

Question:

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

Answer: I₂ and NaOH solution

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

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

Answer: (i) and (ii)

Question: Primary alcohols can be readily oxidised to carboxylic acids by.

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

Answer: (i), (ii) and (iv)

Question: Which of the following is correct order of acidity?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

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

Answer: D < A < B < C

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

• a) CH₃CH₂COOH
• b) CH₃CH₂CH₂COOH
• c) CH₃COOH
• d) None of these

Answer: CH₃CH₂COOH

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 (iv)
• c) Only (iii) and (ii)
• d) (i), (ii), (iii) and (iv)

Answer: Only (iii) and (i)

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Both
• b)

  

• c)

  

• d) None of these

Answer: Both

Question:

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

Answer: (ii) and (iv)

Question:

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

Answer: (i), (ii) and (iv)

Question: Which of the following represents the correct order of the acidity in the given compounds?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

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

Answer: V > II > IV > I > III