CBSE Class 12 Chemistry Aldehyde Ketones And Acids Worksheet Set A

Q1. Name the electrophilic and nucleophilic centre in a carbonyl compound. (1)

Q2. Why is an L-H acidic in carbonyl compounds? (1)

Q3. Presence of –CHO gp in benzaldehyde deactivates the ring towards Eθ sub-reactions, why? (1)

Q4. What is the change in hybridization of a carbonyl carbon atom during NUθ addition reactions? (1)

Q5. What is PCC, give one specific use of this reagent? (1)

Q6. What is DIBAL-H? Give one specific use of this reagent. (1)

Q7. Give formula of Roschelle salt. What is its role in Fehling solu? (1)

Q8. How does benedict solu differ from fehling solu? (1)

Q9. What is formalin? Give one important use of formalin. (1)

Q10. Give one character feature of LiALH4 as a reducing agent. (1)

Question. Ketones [RCOR₁] where R = R₁ = alkyl group. It can be obtained in one step by
(a) oxidation of tertiary alcohol
(b) reaction of acid halide with alcohols
(c) hydrolysis of esters
(d) oxidation of primary alcohol. 
Answer. A

Question. The oxidation of toluene to benzaldehyde by chromyl chloride is called
(a) Etard reaction
(b) Riemer–Tiemann reaction
(c) Wurtz reaction
(d) Cannizzaro’s reaction. 
Answer. A

Question. Reaction between benzaldehyde and acetophenone in presence of dilute NaOH is known as
(a) Aldol condensation
(b) Cannizzaro’s reaction
(c) Cross Cannizzaro’s reaction
(d) Cross Aldol condensation
Answer. D

Question. Which of the following reagents would distinguish cis-cyclopenta-1,2-diol from the trans-isomer?
(a) MnO₂
(b) Aluminium isopropoxide
(c) Acetone
(d) Ozone 
Answer. C

Question. The correct statement regarding a carbonyl compound with a hydrogen atom on its alphacarbon, is
(a) a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as carbonylation
(b) a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as keto-enol tautomerism
(c) a carbonyl compound with a hydrogen atom on its alpha-carbon never equilibrates with its corresponding enol
(d) a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as aldehyde-ketone equilibration.
Answer. B

Question. The product formed by the reaction of an aldehyde with a primary amine is
(a) carboxylic acid
(b) aromatic acid
(c) Schiff ’s base
(d) ketone. 
Answer. C

Question. Reaction of a carbonyl compound with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is
(a) hydrazine in presence of feebly acidic solution
(b) hydrocyanic acid
(c) sodium hydrogen sulphite
(d) a Grignard reagent.
Answer. A

Question. CH₃CHO and C₆H₅CH₂CHO can be distinguished chemically by
(a) Benedict’s test
(b) iodoform test
(c) Tollens’ reagent test
(d) Fehling’s solution test. 
Answer. B

Question. Consider the reaction :
RCHO + NH₂NH₂ → RCH=N — NH₂
What sort of reaction is it?
(a) Electrophilic addition-elimination reaction
(b) Free radical addition-elimination reaction
(c) Electrophilic substitution-elimination reaction
(d) Nucleophilic addition-elimination reaction
Answer. D

Question. Which of the following compounds will give a yellow precipitate with iodine and alkali?
(a) Acetophenone
(b) Methyl acetate
(c) Acetamide
(d) 2-Hydroxypropane
Answer. A,D

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
Answer. B

Question. Which of the following reactions will not result in the formation of carbon-carbon bonds?
(a) Reimer–Tiemann reaction
(b) Cannizzaro reaction
(c) Wurtz reaction
(d) Friedel–Crafts acylation
Answer. B

Question. A strong base can abstract an a-hydrogen from
(a) ketone
(b) alkane
(c) alkene
(d) amine.
Answer. A

Question. Reduction of aldehydes and ketones into hydrocarbons using zinc amalgam and conc. HCl is called
(a) Cope reduction
(b) Dow reduction
(c) Wolff–Kishner reduction
(d) Clemmensen reduction.
Answer. D

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.
Answer. A

Question. A carbonyl compound reacts with hydrogen cyanide to form cyanohydrin which on hydrolysis forms a racemic mixture of a-hydroxy acid. The carbonyl compound is
(a) formaldehyde
(b) acetaldehyde
(c) acetone
(d) diethyl ketone. 
Answer. B

Question. Which of the following is incorrect?
(a) FeCl₃ is used in detection of phenol.
(b) Fehling solution is used in detection of glucose.
(c) Tollens’ reagent is used in detection of unsaturation.
(d) NaHSO₃ is used in detection of carbonyl compound.
Answer. C

Question. First product of the reaction between RCHO and NH₂NH₂ is
(a) RCH NNH₂
(b) RCH NH
(c) RCH₂NH₂
(d) RCON₃ 
Answer. A

Question. An ester (A) with molecular formula, C₉H₁₀O₂ was treated with excess of CH₃MgBr and the complex so formed, was treated with H₂SO₄ to give an olefin
(B). Ozonolysis of (B) gave a ketone with molecular formula C₈H₈O which shows +ve iodoform test. The structure of (A) is
(a) H₃CCH₂COC₆H₅
(b) C₂H₅COOC₆H₅
(c) C₆H₅COOC₂H₅
(d) p-H₃CO – C₆H₄ – COCH₃
Answer. C

Question. Iodoform test is not given by
(a) ethanal
(b) ethanol
(c) 2-pentanone
(d) 3-pentanone. 
Answer. D

Question. Phenylmethanol can be prepared by reducing the benzaldehyde with
(a) CH₃Br and Na
(b) CH₃I and Mg
(c) CH₃Br
(d) Zn and HCl. 
Answer. D

Question. The oxidation of toluene with CrO3 in the presence of (CH₃CO)₂O gives a product A, which on treatment with aqueous NaOH produces
(a) C₆H₅COONa
(b) 2, 4-diacetyl toluene
(c) C₆H₅CHO
(d) (C₆H₅CO)₂O 
Answer. A

Question. When aniline reacts with oil of bitter almonds (C₆H₅CHO) condensation takes place and benzal derivative is formed. This is known as
(a) Schiff ’s base
(b) Benedict’s reagent
(c) Millon’s base
(d) Schiff ’s reagent. 
Answer. A

Question. Compound A has a molecular formula C₂Cl₃OH. It reduces Fehling’s solution and on oxidation, it gives a monocarboxylic acid B. If A is obtained by the action of chlorine on ethyl alcohol, then compound A is
(a) methyl chloride
(b) monochloroacetic acid
(c) chloral
(d) chloroform.
Answer. C

Question. Which of the following compounds will give positive test with Tollens’ reagent?
(a) Acetic acid
(b) Acetone
(c) Acetamide
(d) Acetaldehyde 
Answer. D

Question. (CH₃)₂C CHCOCH₃ can be oxidised to (CH₃)₂C CHCOOH by
(a) chromic acid
(b) NaOI
(c) Cu at 300°C
(d) KMnO₄ 
Answer. B

Question. In which of the following, the number of carbon atoms does not remain same when carboxylic acid is obtained by oxidation?
(a) CH₃COCH₃
(b) CCl₃CH₂CHO
(c) CH₃CH₂CH₂OH
(d) CH₃CH₂CHO 
Answer. A

Question. Acetaldehyde reacts with
(a) electrophiles only
(b) nucleophiles only
(c) free radicals only
(d) both electrophiles and nucleophiles. 
Answer. B

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) I₂ and NaOH.
Answer. D

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

Question. Formalin is an aqueous solution of
(a) fluorescein
(b) formic acid
(c) formaldehyde
(d) furfuraldehyde.
Answer. C

Question. Which of the following compounds gives benzoic acid on hydrolysis?
(a) Chlorobenzene
(b) Benzoyl chloride
(c) Chlorophenol
(d) Chlorotoluene
Answer. B

Question. Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their
(a) formation of intramolecular H-bonding
(b) formation of carboxylate ion
(c) more extensive association of carboxylic acid via van der Waals’ forces of attraction
(d) formation of intermolecular H-bonding.
Answer. D

Question. The correct order of decreasing acid strength of trichloroacetic acid (A), trifluoroacetic acid (B), acetic acid (C) and formic acid (D) is
(a) B > A > D > C
(b) B > D > C > A
(c) A > B > C > D
(d) A > C > B > D
Answer. A

Question. The –OH group of an alcohol or the – COOH group of a carboxylic acid can be replaced by – Cl using
(a) phosphorus pentachloride
(b) hypochlorous acid
(c) chlorine
(d) hydrochloric acid. 
Answer. A

Question. Which one of the following orders of acid strength is correct?
(a) RCOOH > ROH > HOH > HC ≡ CH
(b) RCOOH > HOH > ROH > HC ≡ CH
(c) RCOOH > HOH > HC ≡ CH > ROH
(d) RCOOH > HC ≡ CH > HOH > ROH
Answer. B

Question. Ethyl benzoate can be prepared from benzoic acid by using
(a) ethyl alcohol
(b) ethyl alcohol and dry HCl
(c) ethyl chloride
(d) sodium ethoxide.
Answer. B

Question. Reduction by LiAlH4 of hydrolysed product of an ester gives
(a) two alcohols
(b) two aldehydes
(c) one acid and one alcohol
(d) two acids. 
Answer. A

Question. Which one of the following compounds will react with NaHCO₃ solution to give sodium salt and carbon dioxide?
(a) Acetic acid
(b) n-Hexanol
(c) Phenol
(d) Both (b) and (c)
Answer. A

Question. An acyl halide is formed when PCl₅ reacts with an
(a) amide
(b) ester
(c) acid
(d) alcohol. 
Answer. C

Question. Benzoic acid gives benzene on being heated with X and phenol gives benzene on being heated with Y.
Therefore, X and Y are respectively
(a) soda-lime and copper
(b) Zn dust and NaOH
(c) Zn dust and soda-lime
(d) soda-lime and zinc dust. 
Answer. D

Question. A is a lighter phenol and B is an aromatic carboxylic acid. Separation of a mixture of A and B can be carried out easily by using a solution of
(a) sodium hydroxide
(b) sodium sulphate
(c) calcium chloride
(d) sodium bicarbonate.
Answer. D

Question. The compound formed when malonic acid is heated with urea is
(a) cinnamic acid
(b) butyric acid
(c) barbituric acid
(d) crotonic acid. 
Answer. C

Question. Among the following the strongest acid is
(a) CH₃COOH
(b) CH₂ClCH₂COOH
(c) CH₂ClCOOH
(d) CH₃CH₂COOH
Answer. 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) (ii) > (iii) > (iv) > (i)
(c) (i) > (iv) > (iii) > (ii)
(d) (iv) > (i) > (iii) > (ii)
Answer. A

Question. Match the compounds given in List-I with List-II and select the suitable option using the codes given below.
      List-I                                 List-II
(A) Benzaldehyde           (i) Phenolphthalein
(B) Phthalic anhydride    (ii) Benzoin condensation
(C) Phenyl benzoate       (iii) Oil of wintergreen
(D) Methyl salicylate       (iv) Fries rearrangement
(a) (A)-(iv), (B)-(i), (C)-(iii), (D)-(ii)
(b) (A)-(iv), (B)-(ii), (C)-(iii), (D)-(i)
(c) (A)-(ii), (B)-(iii), (C)-(iv), (D)-(i)
(d) (A)-(ii), (B)-(i), (C)-(iv), (D)-(iii) 
Answer. D

Question. Among the given compounds, the most susceptible to nucleophilic attack at the carbonyl group is
(a) CH₃COOCH₃
(b) CH₃CONH₂
(c) CH₃COOCOCH₃
(d) CH₃COCl 
Answer. D

Question. The relative reactivities of acyl compounds towards nucleophilic substitution are in the order of
(a) acid anhydride > amide > ester > acyl chloride
(b) acyl chloride > ester > acid anhydride > amide
(c) acyl chloride > acid anhydride > ester > amide
(d) ester > acyl chloride > amide > acid anhydride.
Answer. C

Question. Self condensation of two moles of ethyl acetate in presence of sodium ethoxide yields
(a) ethyl propionate
(b) ethyl butyrate
(c) acetoacetic ester
(d) methyl acetoacetate.
Answer. C

Question. Which one of the following esters cannot undergo Claisen self-condensation?
(a) C₆H₅CH₂COOC₂H₅
(b) C₆H₅COOC₂H₅
(c) CH₃CH₂CH₂CH₂COOC₂H₅
(d) C₆H₁₁CH₂COOC₂H₅
Answer. B

Question. Sodium formate on heating yields
(a) oxalic acid and H₂
(b) sodium oxalate and H₂
(c) CO₂ and NaOH
(d) sodium oxalate.
Answer. B

Q.1 Write the IUPAC name of the following compound:- CH₃-O-CH₂-CH(OH)-CH₂-CHO [1]

Q.2 Although phenoxide ion has more no. of resonating structures than carboxylate ion , even though carbxylic

acid is a stronger acid why ? [1]

Q.3 Why Carboxylic acid have higher boiling point than alcohols as alcohol forms strongest inter molecular

hydrogen bonding?[1]

Q.4 Which acid is stronger and why? F₃C-C₆H₄COOH and CH₃C₆H₄COOH .[1]

Q.5 Complete the following reactions:- [2] Red P

(i) CH₃CH₂MgBr + CO₂ ---------> (ii) CH₃CH₂COOH + Cl₂ --------> 

ONE MARK QUESTIONS

1. Write short notes on the following: 

a. Clemmensen reduction

b. Aldol Condensation

c. Rosenmund reduction 

d. Hell-Volhard-Zelinsky

e. Cannizzaro reaction

f. Cross Aldol Condensation reaction

2.Give the structure of the following: 

a. Hex-2-en-4-ynoic acid

b. 3-hydroxy butanal

c. p-Nitropropiophenone

d. 3-Bromo-4-phenylpentanoic acid

e. 3-Methylcyclohexane carbaldehyde

TWO MARK QUESTIONS

1.Explain the following mechanisms:

a) Nucleophilic attack on a carbonyl group of an aldehyde or a ketone.

b) Nucleophilic addition of Grignard reagent on a carbonyl group of an aldehyde or a ketone.

THREE MARK QUESTIONS

1.Distinguish the following:

a) Formic acid and Acetic acid

b) Phenol and benzoic acid

c) Benzaldehyde and ethanal

d) Benzaldehyde and acetophenone

2.Give the structure of the following:

a) Hex-2-en-4-ynoic acid

b) 2,3- dimethylcyclopentane carbaldehyde

c) p-Nitropropiophenone

FIVE MARK QUESTIONS

1.Arrange the following in the increasing order of the property given as indicated:

a) Acetaldehyde, acetone, Di-ter-butylketone, methyl-ter-butylketone (Reactivity towards HCl)

b) 2-Bromobutanoic acid, 3-bromobutanoic acid, 2-methypropanoic acid, butanoic acid (Acid strength)

c) CH₃CHO, CH₃CH₂OH, CH₃OCH₃, CH₃CH₂CH₃ (Boiling point)

d) Ethanal, Propanal, Propanone, Butanone (Nucleophilic addition)

e) Benzoic acid , 4- nitrobenzoic acid , 3,4- dinitrobenzoic acid , 4- methoxybenzoic acid (acid strength)

2.Effect the following conversions:

a. Propanone to propene

b. Propanal to 2-butanone

c. Ethanol to 3-hydroxy butanal

d. Benzaldehyde to 2-hydroxyphenyl aceticacid.

e. Acetaldehyde to isopropyl alcohol

3.Account for the following:

a) Carboxylic acids do not give reactions of carbonyl group 

b) Aldehydes are more reactive to nucleophilic addition than ketones

c) Carboxylic acids have higher boiling points than aldehyde, ketones and even alcohols of comparable molecular mass.(2008)

d) Chloroacetic acid is stronger than acetic acid.

e) There is two –NH₂ groups in semicarbazide , however only one is involved in the formation of semicarbazone.

4.a) An organic compound A contains 69.77% carbon, 11.63% hydrogen and rest oxygen. The molecular mass of the compound is 86. It does not reduce Tollens’ reagent but forms an addition compound with sodium hydrogen sulphite and give positiveiodoform test. On vigorous oxidation it gives ethanoic and propanoic acid. Write the possible structure of the compound A.

b) Write the chemical tests to distinguish between the following pairs of compounds:

i. Acetophenone and Benzophenone

ii. Ethanol and Propanal