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 24 of 34
- A. Iodine is separated from reaction mixture
- B. Carboxylic acid are formed by methyl ketones
- C. Ketone are formed from this reaction
- D. Identification of methanol
Explanation: One of the applications of the iodoform reaction is in the formation of carboxylic acids from methyl ketones.
Correct answer: Carboxylic acid are formed by methyl ketones- A. Butane
- B. Pentane
- C. Isobutanol
- D. Isopentanol
Explanation: Pentane (n-pentane) is an alkane with the molecular formula C5H12. It has a straight-chain structure with no branching or substituents on…
Correct answer: Pentane- A. Painkiller
- B. Preservative and disinfectant
- C. Bleaching and whitening agent
- D. Deodorant
Explanation: Formalin is indeed a powerful preservative and disinfectant. It is derived from formaldehyde, a chemical compound commonly used in various…
Correct answer: Preservative and disinfectant- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: The equation CH3OH + (O)(Na2Cr2O7)/H2SO4 → CH4 doesn't represent a valid chemical reaction.
Correct answer: Option C- A. Alkane
- B. Alcohol
- C. Aldehyde
- D. Ketone
Explanation: Alcohols are the easiest to oxidize compared to other compounds listed.
Correct answer: Alcohol- A. to break H - bonding
- B. to increase collision frequency
- C. to distil product
- D. to avoid any alcohol unreacted
Explanation: Option B is the correct answer.When the temperature of a reaction mixture is increased, the kinetic energy of the molecules also…
Correct answer: to increase collision frequency- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Ketones are indeed less reactive in nucleophilic substitution reactions compared to aldehydes.
Correct answer: Option D- A. Addition of HCN
- B. Addition of NaHSO3
- C. Aldol condensation
- D. Cannizaro's reaction
Explanation: Idoform test needs α - H.The Cannizzaro reaction is a disproportionation reaction that occurs in aldehydes with no alpha hydrogens.
Correct answer: Cannizaro's reaction- A. NaOH + ∆
- B. Na2CO3
- C. HCI + ∆
- D. Ag + ∆
Explanation: When a carbonyl compound reacts with sodium bisulfite (NaHSO3) in the presence of hydrochloric acid (HCl) and heat, it forms a bisulfite…
Correct answer: HCI + ∆- A. ∝-C
- B. β-C
- C. γ-C
- D. δ-C
Explanation: During aldol condensation, the -OH group appears at the beta-carbon position.
Correct answer: β-C- A. 2, 4 - DNPH
- B. K2Cr2O7/H+
- C. Conc H2SO4
- D. Ag mirror test
Explanation: Orange color discharged. when it comes to propanol and propanal, both of them can show a similar visible change when treated with the…
Correct answer: K2Cr2O7/H+- A. Zero
- B. +2
- C. -2
- D. 1
Explanation: Fehling's test is used to detect the presence of reducing sugars, such as aldehydes and certain ketones.
Correct answer: 1- A. Acetaldehyde
- B. Acetylene
- C. Formic acid
- D. Formaldehyde
Explanation: We know that acetylene reacts with ammoniacal AgNO3 and the reaction is known as Tollens's Test.
Correct answer: Acetylene- A. Ag - mirror test
- B. HCN
- C. K2Cr2O7/H+
- D. NaHSO3
Explanation: K2Cr2O7/H+ is a powerful oxidizing agent commonly used in organic chemistry.
Correct answer: K2Cr2O7/H+- A. Electrophilic reactions
- B. Nucleophilic substitution reactions
- C. Nucleophilic addition reactions
- D. Electrophilic substitution reactions
Explanation: Carbonyl compounds, such as aldehydes and ketones, are known for their reactivity with nucleophiles.
Correct answer: Nucleophilic addition reactions- A. oxidation state
- B. methylene group
- C. functional group carbon
- D. beta carbon
Explanation: During the oxidation of ethanol (CH3CH2OH), the alpha carbon refers to the carbon atom adjacent to the hydroxyl group (OH) in the ethanol…
Correct answer: oxidation state- A. Propanone + Tollen's reagent
- B. Butanone + Tollen's reagent
- C. Butanone+ Acidified potassium dichromate
- D. Propanone + Acidified potassium dichromate
Explanation: When propanone is treated with acetic potassium dichromate (K2Cr2O7) in the presence of an acid, such as sulfuric acid (H2SO4), it…
Correct answer: Propanone + Acidified potassium dichromate- A. n-butyl alcohol
- B. Sec-butyl alcohol
- C. Acetophenone
- D. Acetaldehyde
Explanation: The correct answer is a) n-butyl alcohol. It does not answer the iodoform test because it lacks the necessary functional group.
Correct answer: n-butyl alcohol- A. imine
- B. osazone
- C. hyedrazone
- D. oxime
Explanation: The general mechanism of the reaction between aldehyde/ketone and hydroxylamine is shown below.
Correct answer: oxime- A. Alpha carbon
- B. Beta Carbon
- C. Alpha hydroxyl group
- D. Functional group carbon
Explanation: The reaction of lactic acid exclusively takes place at the carboxyl group which is a functional group that consists of a carbon atom…
Correct answer: Functional group carbon