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.
Last updated
679 questions · page 10 of 34
- A. Formaldehyde
- B. Acetaldehyde
- C. Acetone
- D. None of these
Explanation: When calcium acetate and calcium formate are distilled together, they break down and produce acetaldehyde.
Correct answer: Acetaldehyde- A. Red precipitate
- B. Yellow precipitate
- C. Silver mirror
- D. Brick red precipitate
Explanation: Tollen's reagent is an alkaline solution of ammoniacal silver nitrate; the reduction of silver ions in the Tollen's reagent results in a…
Correct answer: Silver mirror- A. To avoid decomposition of product.
- B. To avoid reduction.
- C. To avoid further oxidation to acetic acid.
- D. None of these.
Explanation: Correct option is C.Acetaldehyde is distilled off quickly after formation in the laboratory to avoid further oxidation to acetic acid.
Correct answer: To avoid further oxidation to acetic acid.- A. Substitution and elimination
- B. Substitution
- C. Reduction
- D. Elimination
Explanation: Alkyl halides give two major types of reactions: substitution and elimination.
Correct answer: Substitution and elimination- A. Substitution reaction
- B. None of these
- C. Elimination reaction
- D. Addition reaction
Explanation: Formaldehyde is converted to meta formaldehyde by a polymerization reaction.
Correct answer: Addition reaction- A. Formaldehyde plus lactose
- B. Ethanol plus fructose
- C. Formaldehyde plus fructose
- D. Ethanol plus lactose
Explanation: Formamint is composed of formaldehyde plus lactose.
Correct answer: Formaldehyde plus lactose- A. Carboxylic acid
- B. Primary alcohol
- C. Alkyl Halide
- D. Secondary alcohol
Explanation: The reaction of Grignard's reagent with formaldehyde followed by hydrolysis yields primary alcohol, having a number of carbon atoms equal…
Correct answer: Primary alcohol- A. None of these
- B. Out of the chain
- C. Middle of the chain
- D. Both out of the chain and middle of the chain
Explanation: Formyl is the aldehyde functional group. Removing the R group from an aldehyde gives us the formyl functional group i.e. ―CHO.
Correct answer: Out of the chain- A. Α-hydroxy-ethyl methyl aldehyde
- B. Α-hydroxy-ethyl methyl ketone
- C. Β-hydroxy-ethyl methyl ketone
- D. None of the above
Explanation: For the common naming of a ketone, the two alkyl groups on both the sides of the carbonyl group are first identified, and then Greek…
Correct answer: Α-hydroxy-ethyl methyl ketone- A. Acetaldehyde
- B. Ethylene
- C. Enolate
- D. None of the above
Explanation: The addition of water: Acetylene reacts with water in the presence of dilute sulphuric acid and mercuric sulfate to form an unstable…
Correct answer: Acetaldehyde- A. Tertiary Alcohol
- B. Secondary alcohol
- C. Primary alcohol
- D. None of these
Explanation: Ketones undergo reduction to form secondary alcohol. Formaldehyde undergoes reduction to form methanol while the other aldehydes undergo…
Correct answer: Secondary alcohol- A. One hydroxyl group
- B. Three carbon atoms
- C. Two carbon atoms
- D. Two hydrogen atoms
Explanation: In ketones, the function group (carbonyl group) occurs along the middle of the carbon chain.
Correct answer: Two carbon atoms- A. H2SO4
- B. K2Cr2O7
- C. NaOH
- D. H2O/H+
Explanation: An alkaline catalyst is required for the aldol condensation reaction.
Correct answer: NaOH- A. Acetic acid
- B. Butanoic acid
- C. Propanoic acid
- D. Ester
Explanation: Acetaldehyde oxidation will lead to the formation of acetic acid.Acetaldehyde is a colorless, flammable liquid with a characteristic…
Correct answer: Acetic acid- A. Acid
- B. Base
- C. Oxidizing agents
- D. Pd/C
Explanation: Option A: Acids can catalyze the addition of ammonia and its derivatives by protonation of the nitrogen atom, making it more reactive and…
Correct answer: Acid- A. Because it involves breaking of C-O bond
- B. Because it involves breaking of C-C bond
- C. Because it involves breaking of C-H bond
- D. Because it involves breaking of C=C bond
Explanation: Option A: Because it involves breaking of C-O bond: This option is not correct.
Correct answer: Because it involves breaking of C-C bond- A. Aromatic compounds
- B. Acidic compounds
- C. Carbonyl compounds
- D. Electrophiles
Explanation: Aromatic compounds are organic compounds that contain a cyclic arrangement of atoms with alternating double bonds, known as an aromatic…
Correct answer: Carbonyl compounds- A. K2Cr2O7
- B. PdCl2
- C. FeO, Mo2O3
- D. CuCl2
Explanation: FeO and Mo2O3 are used for the preparation of methanal on an industrial scale.
Correct answer: FeO, Mo2O3- A. Bakelite
- B. Paraldehyde
- C. Metaformaldehyde
- D. All of these
Explanation: Formaldehyde (CH2O) can undergo polymerization to form metaformaldehyde, which is a cyclic trimer consisting of repeating units of…
Correct answer: Metaformaldehyde- A. Fehling's solution test
- B. Benedict's solution test
- C. Silver mirror test
- D. Sodium nitroprusside test
Explanation: The correct option for the reagent in which the cupric citrate complex is formed is B) Benedict's solution test.
Correct answer: Benedict's solution test