Free Aldehydes and Ketones MCQs with Answers
679 Aldehydes and Ketones MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.
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679 questions · page 27 of 34
- A. Acetylides
- B. Paraldehyde
- C. Bakelite
- D. Meta acetaldehyde
Explanation: Acetaldehyde, under certain conditions like concentrated sulfuric acid, can polymerize to form paraldehyde.Paraldehyde is the cyclic…
Correct answer: Paraldehyde- A. Option A: Ethanol
- B. Option B: Aldehyde
- C. Option C: Ketone
- D. Option D: Carboxylic Acid
Explanation: The correct answer is Option B: Aldehyde. Acetals are derivatives of aldehydes or ketones formed by the reaction of two alcohol molecules…
Correct answer: Option B: Aldehyde- A. Methyl-n propyl ketone
- B. Dimethyl ethyl ketone
- C. Methyl neo-propyl ketone
- D. Methyl isopropyl ketone
Explanation: This option is correct because Methyl isopropyl ketone is CH₃ - CO - CH(CH₃)₂
Correct answer: Methyl isopropyl ketone- A. (CH3COO)2 Ca
- B. (HCOO)2Ca
- C. both (a) and (b)
- D. none
Explanation: (a) (CH3COO)2Ca (Calcium Acetate): When heated, calcium acetate breaks down into several products, including acetone (CH3COCH3), calcium…
Correct answer: both (a) and (b)- A. formaldehyde
- B. benzaldehyde
- C. acetaldehyde
- D. acetone
Explanation: Formaldehyde, the smallest and most reactive aldehyde, readily shakes hands with sodium nitroprusside in a swift and vibrant reaction.
Correct answer: formaldehyde- A. CH3OH
- B. CH3COOH+HCOOH
- C. CH3-CH2-OH
- D. Reaction is not possible
Explanation: While K2Cr2O7 in concentrated H2SO4 is a strong oxidizing agent, the presence of a pre-existing carboxylic acid group (CH3COOH) in the…
Correct answer: Reaction is not possible- A. CH3CHO
- B. CH3-CO-CH3
- C. CH3COOH
- D. CH3-CO-CH2-CH3
Explanation: This champion aldehyde readily participates in the Tollen's test, undergoing oxidation to acetic acid.
Correct answer: CH3CHO- A. nucleophile addition
- B. polymerization
- C. oxidation
- D. all
Explanation: The correct answer is:(d) AllHere's why:Aldehydes and ketones are incredibly versatile functional groups and participate in a wide range…
Correct answer: all- A. formaldehyde
- B. acetaldehyde
- C. dimethly ketone
- D. propionaldehyde
Explanation: The aldol condensation reaction involves the self-condensation of aldehydes (or sometimes ketones) containing an α-hydrogen (hydrogen atom…
Correct answer: dimethly ketone- A. 63%
- B. 50%
- C. 52%
- D. 8%
Explanation: Formalin is a solution of formaldehyde (CH₂O) in water, and its concentration is often expressed in terms of percentage by weight.
Correct answer: 63%- A. НСНО
- B. CH3CHO
- C. CH3-CH2-CHO
- D. None of the above
Explanation: All three aldehydes listed (formaldehyde, acetaldehyde, and propionaldehyde) possess a carbonyl group (C=O) and an electrophilic carbon…
Correct answer: None of the above- A. pink
- B. black
- C. yellow
- D. brick red
Explanation: Fehling's solution is a powerful tool for identifying aldehydes (and some α-hydroxy ketones).
Correct answer: brick red533. Which of the following compounds has the empirical formula CH20 and reacts with sodium hydroxide?
- A. carbonic acid
- B. ethanol
- C. acetic acid
- D. methanoic acid
Explanation: Empirical formula: All the options share the same empirical formula, CH₂O.
Correct answer: acetic acid- A. Acid
- B. Base
- C. Both a and b
- D. None
Explanation: Nucleophilic addition reactions are diverse and can be catalyzed by both acids and bases, depending on the specific reaction mechanism and…
Correct answer: Both a and b- A. Tartaric acid
- B. Propanoic acid
- C. Lactic acid
- D. Valeric acid
Explanation: When acetaldehyde cyanohydrin, CH₃CH(OH)CN, undergoes acid hydrolysis, it undergoes two key reactions:Cleavage of the cyanohydrin group…
Correct answer: Lactic acid- A. Alcohol
- B. Ketone
- C. Both a & b
- D. None of the above
Explanation: Acetal, also known as 1,1-diethoxyethane (CH₃CH₂OCH₂CH₃), undergoes acid hydrolysis in the presence of strong acids like H₂SO₄ or HCl.
Correct answer: Both a & b- A. P° alcohol
- B. T° alcohol
- C. S° alcohol
- D. Not possible
Explanation: When aldehydes (RCHO) undergo reduction, they gain two hydrogen atoms and get converted to primary alcohols (RCH₂OH).
Correct answer: P° alcohol- A. 3- hexanone
- B. acetone
- C. butanone
- D. 2- pentanone
Explanation: This molecule has a methyl group (CH₃) and an ethyl group (CH₂CH₃) attached to the carbonyl carbon.
Correct answer: acetone- A. hydrogen ion
- B. hydride ion
- C. oxide ion
- D. methoxide ion
Explanation: The Cannizzaro reaction, named after Stanislao Cannizzaro, involves the disproportionation of two molecules of an aldol without α-hydrogen…
Correct answer: hydride ion- A. ethanol and methanol
- B. acetaldehyde and methanal
- C. acetone and diethyl ketone
- D. all of the above
Explanation: The iodoform test relies on the reaction of a compound with excess iodine and sodium hydroxide to form iodoform (CHI₃), a yellow…
Correct answer: all of the above