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 21 of 34
- A. NH2NH2
- B. NH2NHCONH2
- C. C6H5NHNH2
- D. NH2-OH
Explanation: Semicarbazide is the chemical compound with the formula OC(NH2)(N2H3). It is a water-soluble white solid.
Correct answer: NH2NHCONH2- A. Both alkyl groups are more electron-donating than that of aldehyde
- B. Both alkyl groups produce more steric hindrance
- C. Both alkyl group decrease more polarity of carbonyl groups of ketone
- D. Both alkyl groups are electron-withdrawing groups and increase polarity
Explanation: a. Both alkyl groups are more electron donating than that of aldehyde - This statement is incorrect.
Correct answer: Both alkyl groups are more electron-donating than that of aldehyde- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Explanation for this question will be added soon!
Correct answer: Option A- A. Butane
- B. 2-butanone
- C. 1-butanone
- D. Butanal
Explanation: The correct answer is "d) Butanal" as it has the most stable conjugate base due to resonance stabilization.
Correct answer: Butanal- A. Nucleophilic character of the attacking reagent only
- B. Electrophilic character of the carbonyl carbon atom only
- C. Electrophilic character of the attacking reagent only
- D. Nucleophilic character of the carbonyl carbon atom only
Explanation: A base-catalyzed reaction in a carbonyl compound increases the nucleophilic character of the attacking reagent only.
Correct answer: Nucleophilic character of the attacking reagent only- A. Having no a-hydrogen
- B. Having a-hydrogen
- C. Having a-methyl group
- D. Difficult to predic
Explanation: dol condensartion has the limitation that the compounds should have alpha hydrogen.
Correct answer: Having no a-hydrogen- A. p-alcohols
- B. s-alcohols
- C. ter-alcohols
- D. Carboxylic acids
Explanation: Primary alcohols on oxidation give aldehydes.
Correct answer: p-alcohols- A. Formaldehyde
- B. Benzaldehyde
- C. Acetaldehyde
- D. Trimethylacetaldehyde
Explanation: Acetaldehyde has alpha hydrogen that is the hydrogen attached to the carbon adjacent to carbonyl carbon hence it undergoes cannizaros…
Correct answer: Acetaldehyde- A. Alcohols
- B. Aldehydes
- C. Amines
- D. Carboxylic acids
Explanation: The correct option for the class of compound that gives a positive result when tested with 2,4-dinitrophenylhydrazine reagent and forms…
Correct answer: Aldehydes- A. Alkaline aqueous iodine
- B. Aqueous bromine
- C. Fehiling's reagent
- D. Tollen's reagent
Explanation: The correct option for the reagent that could give a positive result when testing the exhaled breath of diabetics containing propanone for…
Correct answer: Alkaline aqueous iodine- A. CH3CH2CHO
- B. CH3CH2OH
- C. CH3CH2COCH3
- D. CH3CH2COCH2CH3
Explanation: The correct option for the organic compound that would give the specified results is B) CH3CH2OH (Ethanol).
Correct answer: CH3CH2OH- A. Aldehyde is given priority
- B. Aldehyde group is present at terminal
- C. Aldehyde is parent
- D. None of these
Explanation: The correct reason why, in IUPAC nomenclature, the aldehyde group in all aldehydes is given position 1, and its position is not mentioned…
Correct answer: Aldehyde group is present at terminal- A. Red precipitate
- B. Yellow precipitate
- C. Silver mirror
- D. Brick red precipitate
Explanation: The correct result of the reaction between aldehydes and Tollen's reagent is C) Silver mirror.
Correct answer: Silver mirror- A. Benzaldehyde
- B. Trimethyl acetaldehyde
- C. Formaldehyde
- D. Acetaldehyde
Explanation: The correct answer is D) Acetaldehyde. Acetaldehyde does not undergo the Cannizzaro's reaction due to the absence of a suitable…
Correct answer: Acetaldehyde- A. 2-Hydroxypropanoic acid
- B. 2-Methy1propanenitrile
- C. Hydroxyacetonitrile
- D. 2-Hydroxypropane
Explanation: CH2O + HCN → HOCH2CN. The reaction of cyanide with formaldehyde results in the substitution of a hydrogen atom with the cyanide group…
Correct answer: Hydroxyacetonitrile- A. Aldehydes
- B. Imines
- C. Amines
- D. Nitriles
Explanation: Compounds having a cyanide group are called nitriles. Therefore, option d is correct.
Correct answer: Nitriles- A. Alkanone
- B. Adduct
- C. Cyanohydrin
- D. Alkenes
Explanation: An adduct is a chemical compound formed by the combination of two or more molecules or chemical groups.
Correct answer: Adduct- A. Silver nitrate
- B. Silver acetate
- C. Cupric tartrate
- D. Cupric citrate
Explanation: Tollen's reagent is an ammoniacal solution of silver nitrate. It's used to test for the presence of aldehydes, which are oxidized to…
Correct answer: Silver nitrate- A. More electron donating groups
- B. Less steric hindrance
- C. Both A and B
- D. None of these
Explanation: The reactivity difference between aldehydes and ketones is mainly due to steric hindrance.
Correct answer: Less steric hindrance- A. Aldehyde
- B. Alcohol
- C. Esters
- D. Ketones
Explanation: Both camphor and menthone are ketones. Ketones have a carbonyl group (C=O) in the middle of a carbon chain.
Correct answer: Ketones