CBSE Class 12 Chemistry Aldehydes Ketones Chapter Notes

Question. Schiff's reagent gives pink colour with:
a. Aldehydes
b. Ethers
c. Ketones
d. Carboxylic acid
Answer : A
 

Question. Acid to give the corresponding hydrocarbon:
a. Acetamide
b. Acetic acid
c. Ethyl acetate
d. Butan–2–one
Answer : D
 

Question. Fehling solution is:
a. CuSO₄ + lime
b. CuSO₄ + NaOH(aq)
c. CuSO₄ + Na₂ CO₃
d. None of these
Answer : D

Question. A compound has a vapour density of 29. On warming an aqueous solution of alkali, it gives a yellow precipitate.
The compound is:
a. CH₃ CH₂ CHO
b. CH₃ CHOHCH₃
c. CH₃ COCH₃
d. CH₃ CH₂ COOH
Answer : A

Question. Which of the following would undergo aldol condensation?

Answer : C

Question. Which one of the following on oxidation will not give a carboxylic acid with the same number of carbon atoms?
a. CH₃ COCH₃
b. CCl₃ CH₂ CHO
c. CH₃ CH₂ CH₂ OH
d. CH₃ CH₂ CHO
Answer : A

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
Answer : D
 

Question. Which of the following will undergo aldol condensation?
a. Acetaldehyde
b. Propanaldehyde
c. Benzaldehyde
d. Trideuteroacetaldehyde
Answer : A, B, D
 

Question. Which of the following will give yellow precipitate with?
I₂ / NaOH
a. ICH COCH CH
b. CH₃ COOCOCH₃
c. CH₃ CONH₂
d. CH₃ CH(OH)CH₂ CH₂
Answer : A, D
 

Question. Which of the following reactions give benzo phenone?

Answer : B
 

Question. Which of the following aldehydes give red precipitate with Fehling solution?
a. Benzaldehyde
b. Salicylaldehyde
c. Acetaldehyde
d. None of these
Answer : C

Question. The order of susceptibility of nucleophilic attack on aldehydes follows the order:
a. 1° > 3° > 2°
b. 1° > 2° > 3°
c. 3° > 2° > 1°
d. 2° > 3° > 1°
Answer : B

Question. Cannizzaro reaction is not shown by:
a. HCHO
b. C₆ H₅ CHO
c. CH₃ CHO
d. All of these
Answer : C

Question. Which of the following are examples of aldol condensation?

Answer : A, B
 

Question. Reaction of acetaldehyde with HCN followed by hydrolysis gives a compound which shows?
a. Optical isomerism
b. Geometrical isomerism
c. Metamerism
d. Tautomerism
Answer : A

Question. IUPAC name of CH₃ COCH₃ is:
a. Acetone
b. 2-propanone
c. Dimethyl ketone
d. Propanal
Answer : B

Question. IUPAC name of CCl₃ CHO is:
a. Chloral
b. Trichloro acetaldehyde
c. 1, 1, 1-trichloroethanal
d. 2, 2, 2-trichloroethanal
Answer : D

Question. Which of the following will respond to Feling’s solution?

Answer : CD
 

Question. Which of the following compounds can be used as a source of Br⁺ ?

Answer : AC
 

Question. Which of the aldehyde is most reactive?
a. C₆ H₅ −CHO
b. CH₃ CHO
c. HCHO
d. All the equally reactive
Answer : C

Assertion and Reason
 

Note: Read the Assertion (A) and Reason (R) carefully to mark the correct option out of the options given below:
a. If both assertion and reason are true and the reason is the correct explanation of the assertion.
b. If both assertion and reason are true but reason is not the correct explanation of the assertion.
c. If assertion is true but reason is false.
d. If the assertion and reason both are false.
e. If assertion is false but reason is true.
 

Question. Assertion: Lower aldehyde and ketones are soluble in water but the solubility decreases as molecular mass increases.
Reason: Aldehydes and ketones can be distinguished by Tollen's reagent.
Answer : B
 

Question. Assertion: Formaldehyde cannot be prepared by Rosenmund's reduction.
Reason: Acid chlorides can be reduced into aldehydes with hydrogen in boiling xylene using palladium or platinum as a catalyst supported on barium sulphate. This is known as Rosenmund's reduction.
Answer : B

Question. Assertion: Acetophenone and benzophenone can be distinguished by iodoform test.
Reason: Acetophenone and benzophenone both are carbonyl compounds.
Answer : B
 

Question. Assertion: Isobutanal does not give iodoform test
Reason: It does not have α- hydrogen.
Answer : C
 

Question. Assertion: Aldol condensation can be catalysed both by acids and bases.
Reason: β- Hydroxy aldehydes or ketones readily undergo acid catalysed dehydration.
Answer : B
 

Question. Assertion: Ketones are less reactive than aldehydes.
Reason: Ketones do not give schiff's test.
Answer : B
 

Question. Assertion: CH₃ CHOreacts with 3 NH to form urotropine.
Reason: Urotropine is used as medicine in case of urinary troubles.
Answer : E
 

Question. Assertion: Acetaldehyde on treatment with alkaline gives aldol.
Reason: Acetaldehyde molecules contains α hydrogen atom.
Answer : A
 

Question. Assertion: Acetylene on treatment with alkaline KMnO₄ produce acetaldehyde.
Reason: Alkaline KMnO₄ is a reducing agent.
Answer : D

Question. Assertion: Oximes are less acidic than hydroxyl amine.
Reason: Oximes of aldehydes and ketones show geometrical isomerism.
Answer : E

Integer
 

Question. In the scheme given below, the total number of intramolecular aldol condensation products formed from ‘Y’ is

Answer : 1
 

Question. Consider all possible isomeric ketones including stereiosmers of MW = 100. All these isomers are independently reacted with 4 NaBH (Note: Stereoisomers are also reacted separately). The total number of ketones that give a racemic product(s) is/are:
Answer : 5
 

Question. How many aldol products can form when 2-butanone and propanaldehyde reacts in presence of dilute base?
Answer : 6

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