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 16 of 34
- A. Acid halides
- B. Alcohols
- C. Aldehydes
- D. Ketones
Explanation: Tollens' reagent, also known as the silver mirror test, is a chemical test used to detect the presence of aldehydes.
Correct answer: Aldehydes- A. Amphoteric
- B. Nucleophilic
- C. Electrophobic
- D. Electrophilic
Explanation: Nucleophilic - Correct. Base-catalyzed reactions often involve nucleophiles, which donate electron pairs to electrophiles.
Correct answer: Nucleophilic- A. The reaction is catalyzed by concentrated H₂SO₄
- B. Pentan-2-one and HCN react to give a chiral product
- C. The reaction is a condensation reaction
- D. The reaction is nucleophilic substitution
Explanation: Pentan-2-one and HCN react to give a chiral product - Correct. The addition of HCN to an asymmetric ketone produces a chiral cyanohydrin.
Correct answer: Pentan-2-one and HCN react to give a chiral product304. Acetone gives:
- A. Fehling solution test positive
- B. Silver mirror test positive
- C. Lucas test positive
- D. Iodoform test positive
- E. Benedicts test positive
Explanation: Acetone reacts with excess iodine in a basic condition to form the carboxylic acid with one less carbon (ethanoic acid), and a yellow…
Correct answer: Iodoform test positive305. Nylon 4.6 is:
- A. Addition polymer
- B. Condensation polymer of hexandioic acid & 1,4 diaminobutane
- C. It is an ester
- D. Condensation polymer
- E. It is a carboxylic acid
Explanation: The correct option is option B. Nylon 4,6 is a condensation polymer of hexanedioic acid (adipic acid) and 1,4-diamino butane.
Correct answer: Condensation polymer of hexandioic acid & 1,4 diaminobutane- A. Ketones are more easily oxidized
- B. It is always difficult to oxidize aldehyde
- C. Mild oxidizing agent & strong oxidizing agent both
- D. Only strong oxidizing agent
- E. Only mild oxidizing agent
Explanation: Aldehydes can react with both mild oxidizing agents and strong oxidizing agents.Aldehydes have a carbonyl group (C=O) where the carbon is…
Correct answer: Mild oxidizing agent & strong oxidizing agent both307. Acetophenone is an:
- A. Aliphatic ketones
- B. Phenol
- C. Carboxylic acid
- D. Aldehyde
- E. Aromatic ketones
Explanation: This is the correct option. Acetophenone is an aromatic ketone. It consists of a phenyl group (aromatic ring) attached to a carbonyl group…
Correct answer: Aromatic ketones- A. Aldehyde
- B. Acetal
- C. Carboxylic acid
- D. Acetone
- E. Ketone
Explanation: The addition product of formaldehyde and ethyl alcohol is option (b): Acetal.When formaldehyde (HCHO) reacts with ethyl alcohol (C2H5OH)…
Correct answer: Acetal- A. Adduct
- B. Hydronium ion
- C. Oxonium ion
- D. Phenoxide ion
Explanation: The reaction between phenol and formaldehyde is known as the Mannich reaction.
Correct answer: Adduct- A. 3-oxo hexanal
- B. 3-one hexanal
- C. 2-oxo hexanol
- D. 3-one hexanol
Explanation: In the given compound, there is a carbonyl group (C=O) located at the third carbon atom (counting from the left) of the carbon chain.
Correct answer: 3-oxo hexanal- A. Fehling solution is used in detection of glucose
- B. NaHSO3 is used in detection of carbonyl compounds
- C. FeCl3 is used in detection of phenols
- D. Tollen's reagent is used in detection of Aldehyde
Explanation: The correct answer is: Option B: NaHSO3 is used in detection of carbonyl compounds.
Correct answer: NaHSO3 is used in detection of carbonyl compounds- A. Electrophilic addition
- B. Electrophilic substitution
- C. Nucleophilic substitution
- D. Nucleophilic addition
Explanation: It is an example of nucleophilic addition. Acetone reacts with HCN to form a cyanohydrin.
Correct answer: Nucleophilic addition- A. 2.4-NDPH reaction
- B. Aldol condensation reaction
- C. Clemmenson reaction
- D. Cannizaro reaction
Explanation: The Cannizzaro reaction is a disproportionation reaction of an aldehyde in the presence of a strong base, such as 50% NaOH.
Correct answer: Cannizaro reaction- A. Alcohol
- B. Carboxylic acid
- C. Alkane
- D. Aldehyde
Explanation: The correct answer is Alcohol. During catalytic reduction, hydrogen is added to the carbonyl group of aldehydes and ketones, converting…
Correct answer: Alcohol- A. Methoxy ethane
- B. Ethoxy ethane
- C. Methyl ethane
- D. Cyclohexanecarbaldehyde
Explanation: The correct IUPAC name for the compound CH3-O-C2H5 is Methoxy ethane.
Correct answer: Methoxy ethane- A. Methanal
- B. Acetic acid
- C. Ethyl alcohol
- D. Acetore
Explanation: Methanal is an aldehyde that can undergo oxidation with Tollen's reagent to produce metallic silver.
Correct answer: Methanal- A. Primary alcohol
- B. Tertiary alcohol
- C. Alcohol
- D. Dihydric alcohol
- E. Secondary alcohol
Explanation: Ketones reduce to form secondary alcohols in the presence of lithium aluminum hydride (LiAlH₄).
Correct answer: Secondary alcohol- A. Ozonolysis
- B. Wolff-Kishner reaction
- C. Grignard reaction
- D. Friedel-Craft reaction
- E. None of these
Explanation: The Wolff-Kishner reaction is a chemical reaction used to reduce aldehydes or ketones to alkanes.
Correct answer: Wolff-Kishner reaction- A. Nucleophilic substitution
- B. Nucleophilic addition
- C. Electrophilic substitution
- D. Free radical addition
Explanation: The reaction of formaldehyde (HCHO) with hydrogen cyanide (HCN) involves a nucleophilic addition rather than a nucleophilic…
Correct answer: Nucleophilic addition- A. CO2
- B. Cu2O
- C. AgO
- D. SO2
Explanation: The blue color of Fehling's solution changes to red when warmed with an aldehyde due to the formation of Cu₂O (copper(I) oxide) because of…
Correct answer: Cu2O