CUET UG Chemistry Booster Test - 2 Preparation of Amines
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QUESTION 1 OF 20
The chemical reaction where nitro compounds are converted to amines using H₂ gas over a finely divided Pd catalyst represents which type of organic conversion?
QUESTION 2 OF 20
When nitro compounds are reduced using metals like Fe, the reaction environment must strictly be:
QUESTION 3 OF 20
During the catalytic hydrogenation of nitroethane utilizing a finely divided nickel catalyst, the product formed has the IUPAC name:
QUESTION 4 OF 20
Regarding catalysts in nitro reduction:
(A) Palladium effectively catalyzes the reduction.
(B) Platinum is also an effective catalyst.
(C) Catalysts must be finely divided for optimal function.
(D) Nitroalkanes can be similarly reduced to alkanamines.
QUESTION 5 OF 20
QUESTION 6 OF 20
QUESTION 7 OF 20
Arrange the following alkyl halides in decreasing order of their reactivity in ammonolysis:
(A) CH₃–Cl
(B) CH₃–I
(C) CH₃–Br
QUESTION 8 OF 20
Ammonolysis of alkyl halides is defined by:
(A) The cleavage of the C–X bond by an NH₃ molecule.
(B) The initial primary amine behaving as a nucleophile.
(C) The eventual formation of quaternary ammonium salts.
(D) Being a nucleophilic substitution reaction.
QUESTION 9 OF 20
Why must the ammonolysis reaction be carried out in a sealed tube at 373 K?
QUESTION 10 OF 20
The temperature designated for ammonolysis is 373 K. The unit 'K' corresponds to an absolute scale where 373 equates to which value in degrees Celsius (°C)?
QUESTION 11 OF 20
To obtain a primary amine as the major product rather than a mixture during ammonolysis, which condition must be met?
QUESTION 12 OF 20
List 1 (Reacting Species) | List 2 (Resulting Product)
| List 1 | List 2 |
|---|---|
| 1. Primary amine + RX | a. Secondary amine |
| 2. Secondary amine + RX | b. Tertiary amine |
| 3. Tertiary amine + RX | c. Quaternary ammonium salt |
| 4. Ammonium salt + Strong Base | d. Free amine |
QUESTION 13 OF 20
The chemical reduction of nitriles with LiAlH₄ is specifically favored when synthesizing primary amines designed for:
QUESTION 14 OF 20
Which specific type of amine is successfully produced when a nitrile undergoes catalytic hydrogenation?
QUESTION 15 OF 20
What is the IUPAC name of the primary amine formed when Benzamide is completely reduced with LiAlH₄?
QUESTION 16 OF 20
The conversion of an amide directly into an amine utilizing LiAlH₄ is best classified chemically as:
QUESTION 17 OF 20
In the Gabriel phthalimide synthesis process:
(A) Phthalimide is treated with ethanolic KOH.
(B) A potassium salt of phthalimide is generated.
(C) The salt is subsequently heated with an alkyl halide.
(D) Alkaline hydrolysis finally yields a primary amine.
QUESTION 18 OF 20
Which of the following compounds CANNOT be prepared using Gabriel phthalimide synthesis?
QUESTION 19 OF 20
Identify the specific reaction type illustrated:
Amide + Br₂ + NaOH(aq) → Primary amine + Carbon loss
QUESTION 20 OF 20
About the Hoffmann bromamide degradation:
(A) The amine formed contains one carbon more than the amide.
(B) An alkyl or aryl group explicitly migrates.
(C) Migration occurs from the carbonyl carbon to the nitrogen atom.
(D) The final amine contains one carbon less than the starting amide.
Test Complete!
Answer Review
1 The chemical reaction where nitro compounds are converted to amines using H₂ gas over a finely divided Pd catalyst represents which type of organic conversion?
�� Hydrogen gas is used as the reducing agent. �� Palladium acts as a catalyst. �� Nitro group is converted into an amino group.
- Nitro compounds are reduced to amines by passing hydrogen gas in the presence of finely divided catalysts such as Pd, Pt, or Ni. Example: R–NO₂ + 3H₂ → R–NH₂ + 2H₂O → Since hydrogen is added in the presence of a catalyst, the process is called catalytic hydrogenation.
- �� Option B → No electrophilic substitution occurs.
- �� Option C → No nucleophile replaces a group.
- �� Option D → No elimination of atoms/groups takes place.
Used
- Contextual/Tonal Matching
Application:
- �� Identify the reaction from the reagents H₂ and Pd.
Final Logic:
- �� H₂ + catalyst = catalytic hydrogenation.
- H₂ + Pd = Hydrogenation
2 When nitro compounds are reduced using metals like Fe, the reaction environment must strictly be:
�� Fe/HCl reduction is carried out in acidic medium. �� Acid supplies protons required for reduction. �� Amines are produced efficiently.
- Nitro compounds can be reduced using metals such as iron in the presence of hydrochloric acid. Example: R–NO₂ + Fe/HCl → R–NH₂ → The reaction requires an acidic medium for successful reduction.
- �� Option A → Strongly basic medium is not used.
- �� Option B → Neutral medium is ineffective.
- �� Option D → Alkaline medium is not the standard condition.
Used
- Elimination
Application:
- �� Recall Fe/HCl reduction conditions.
Final Logic:
- �� Fe reduction proceeds in acidic medium.
- Fe + HCl = Acidic Reduction
3 During the catalytic hydrogenation of nitroethane utilizing a finely divided nickel catalyst, the product formed has the IUPAC name:
�� Nitro group converts into amino group. �� Carbon chain remains unchanged. �� Nitroethane becomes ethanamine.
- Nitroethane (CH₃CH₂NO₂) undergoes reduction: CH₃CH₂NO₂ → CH₃CH₂NH₂ → The product CH₃CH₂NH₂ is called ethanamine.
- �� Option A → One-carbon amine.
- �� Option C → Secondary amine.
- �� Option D → Starting material itself.
Used
- Substitution
Application:
- �� Replace –NO₂ with –NH₂.
Final Logic:
- �� Nitroethane → Ethanamine.
- NO₂ → NH₂
4 Regarding catalysts in nitro reduction:
(A) Palladium effectively catalyzes the reduction.
(B) Platinum is also an effective catalyst.
(C) Catalysts must be finely divided for optimal function.
(D) Nitroalkanes can be similarly reduced to alkanamines.
�� Pd and Pt are effective catalysts. �� Finely divided catalysts provide large surface area. �� Nitroalkanes form alkanamines on reduction.
- Palladium, platinum, and nickel are commonly used catalysts. → Catalysts are finely divided to increase surface area and hydrogen adsorption. → Nitroalkanes and nitroarenes are both reduced to corresponding amines. Therefore all statements are correct.
- �� Option B → Omits statement C.
- �� Option C → Omits statement A.
- �� Option D → Omits statement B.
Used
- Option Grouping
Application:
- �� Verify each statement individually.
Final Logic:
- �� All four statements are correct.
- Pd, Pt, Ni + H₂ = Amines
5
�� FeCl₂ is formed during reaction. �� FeCl₂ undergoes hydrolysis. �� HCl is regenerated continuously.
- During Fe/HCl reduction, FeCl₂ is produced. → FeCl₂ undergoes hydrolysis and releases HCl back into the reaction mixture. → Thus only a small initial quantity of HCl is needed, making the process economical and efficient.
- �� Option A → Not the reason stated in NCERT.
- �� Option B → FeCl₂ actively participates through hydrolysis.
- �� Option D → Secondary amine formation is unrelated.
Used
- Contextual/Tonal Matching
Application:
- �� Extract the exact reason from the passage.
Final Logic:
- �� Hydrolysis of FeCl₂ regenerates HCl.
- FeCl₂ → HCl Returns
6
�� FeCl₂ regenerates HCl. �� Acid is recycled. �� Small initial amount is sufficient.
- Since FeCl₂ releases HCl through hydrolysis, hydrochloric acid is continuously regenerated. → Therefore, only a small amount of HCl is required initially to start the reaction.
- �� Option A → Initial HCl is still necessary.
- �� Option C → Cooling is not mentioned.
- �� Option D → FeCl₂ formation does not stop the reaction.
Used
- Elimination
Application:
- �� Select the statement directly supported by the passage.
Final Logic:
- �� Regeneration of HCl reduces acid requirement.
- Small HCl, Big Job
7 Arrange the following alkyl halides in decreasing order of their reactivity in ammonolysis:
(A) CH₃–Cl
(B) CH₃–I
(C) CH₃–Br
�� Better leaving group means higher reactivity. �� I⁻ leaves most easily. �� Cl⁻ leaves least easily.
- Reactivity in ammonolysis depends on C–X bond cleavage. Leaving group ability: I⁻ > Br⁻ > Cl⁻ Therefore: CH₃I > CH₃Br > CH₃Cl
- �� Option A → Reverse order.
- �� Option C → Places bromide above iodide.
- �� Option D → Incorrect Cl–Br order.
Used
- Ordering
Application:
- �� Rank halides by leaving group ability.
Final Logic:
- �� I > Br > Cl.
- I Beats Br Beats Cl
8 Ammonolysis of alkyl halides is defined by:
(A) The cleavage of the C–X bond by an NH₃ molecule.
(B) The initial primary amine behaving as a nucleophile.
(C) The eventual formation of quaternary ammonium salts.
(D) Being a nucleophilic substitution reaction.
�� NH₃ cleaves C–X bond. �� Primary amine acts as nucleophile. �� Further alkylation can produce quaternary salts.
- Ammonolysis is a nucleophilic substitution reaction where NH₃ replaces the halogen atom. → The primary amine formed can react further as a nucleophile, producing secondary amines, tertiary amines, and finally quaternary ammonium salts. Thus all statements are correct.
- �� Options A, B, D omit one or more correct statements.
Used
- Option Grouping
Application:
- �� Verify each statement independently.
Final Logic:
- �� All four statements are true.
- NH₃ → 1° → 2° → 3° → Quaternary
9 Why must the ammonolysis reaction be carried out in a sealed tube at 373 K?
�� Ammonia is volatile. �� Heating causes gas loss. �� Sealed tube prevents escape.
- Ammonolysis is performed at 373 K using ethanolic ammonia. → Since ammonia is volatile, heating in an open vessel would cause its escape. → A sealed tube maintains sufficient ammonia concentration for the reaction.
- �� Option B → No solidification occurs.
- �� Option C → The tube is not a catalyst.
- �� Option D → No selective precipitation occurs.
Used
- Contextual/Tonal Matching
Application:
- �� Connect ammonia volatility with reaction setup.
Final Logic:
- �� Sealed tube prevents ammonia loss.
- Hot NH₃ Needs Closed Tube
10 The temperature designated for ammonolysis is 373 K. The unit 'K' corresponds to an absolute scale where 373 equates to which value in degrees Celsius (°C)?
�� K = °C + 273. �� 373 − 273 = 100. �� Therefore 373 K equals 100°C.
- Conversion formula: °C = K − 273 → Therefore: 373 − 273 = 100°C Hence 373 K corresponds to 100°C.
- �� Option B → Kelvin offset value.
- �� Option C → Same numerical value but wrong scale.
- �� Option D → Corresponds to 273 K.
Used
- Dimensional/Unit Analysis
Application:
- �� Convert Kelvin to Celsius.
Final Logic:
- �� 373 K = 100°C.
- K − 273 = °C
11 To obtain a primary amine as the major product rather than a mixture during ammonolysis, which condition must be met?
�� Primary amines can further react with alkyl halides. �� Excess ammonia suppresses further alkylation. �� This increases the yield of primary amine.
- During ammonolysis, the initially formed primary amine is more nucleophilic than ammonia and can further react with alkyl halides to produce secondary amines, tertiary amines, and quaternary ammonium salts. → To minimize these side reactions and obtain primary amine as the major product, a large excess of ammonia is used. → Excess NH₃ increases the probability of alkyl halide reacting with ammonia rather than with the amine product.
- �� Option A → Excess alkyl halide promotes formation of higher amines.
- �� Option C → 500 K is not the required condition.
- �� Option D → Palladium catalyst is used in hydrogenation, not ammonolysis.
Used
- Elimination
Application:
- �� Identify the condition that suppresses further alkylation.
Final Logic:
- �� Excess NH₃ favors formation of primary amine.
- More NH₃ = More 1° Amine
12 List 1 (Reacting Species) | List 2 (Resulting Product)
| List 1 | List 2 |
|---|---|
| 1. Primary amine + RX | a. Secondary amine |
| 2. Secondary amine + RX | b. Tertiary amine |
| 3. Tertiary amine + RX | c. Quaternary ammonium salt |
| 4. Ammonium salt + Strong Base | d. Free amine |
�� Primary amine undergoes alkylation to secondary amine. �� Secondary amine gives tertiary amine. �� Tertiary amine gives quaternary salt.
- Successive alkylation during ammonolysis proceeds as: Primary amine + RX → Secondary amine Secondary amine + RX → Tertiary amine Tertiary amine + RX → Quaternary ammonium salt Ammonium salt + Strong Base → Free amine Thus: 1 → a 2 → b 3 → c 4 → d
- �� Option B → Incorrect product sequence.
- �� Option C → Secondary amine does not directly produce quaternary salt.
- �� Option D → Completely mismatched progression.
Used
- Option Grouping
Application:
- �� Follow the sequential alkylation pathway.
Final Logic:
- �� Each alkylation step increases substitution by one level.
- 1° → 2° → 3° → 4° Salt
13 The chemical reduction of nitriles with LiAlH₄ is specifically favored when synthesizing primary amines designed for:
�� Nitrile reduction forms primary amines. �� Carbon chain length increases by one carbon. �� Useful for ascent of amine series.
- Nitriles are reduced by LiAlH₄ to give primary amines. Example: CH₃CN → CH₃CH₂NH₂ → The resulting amine contains one additional carbon compared with the starting amine from which the nitrile may have been prepared. → Therefore this method is widely used for the ascent of amine series.
- �� Option A → Chain length does not decrease.
- �� Option C → Primary amines are formed.
- �� Option D → Tertiary amines are not produced.
Used
- Contextual/Tonal Matching
Application:
- �� Recall the synthetic utility of nitrile reduction.
Final Logic:
- �� Nitrile reduction increases carbon chain length by one.
- Nitrile Reduction = +1 Carbon
14 Which specific type of amine is successfully produced when a nitrile undergoes catalytic hydrogenation?
�� Nitriles are reduced to amines. �� The –CN group converts into –CH₂NH₂. �� Product is always a primary amine.
- Catalytic hydrogenation of nitriles converts the nitrile group into a primary amino group. General reaction: R–C≡N + 2H₂ → R–CH₂NH₂ → The product contains one amino group attached to a carbon chain and is therefore a primary amine.
- �� Option A → Secondary amines are not formed directly.
- �� Option C → Quaternary salts are not formed.
- �� Option D → Imides are unrelated products.
Used
- Elimination
Application:
- �� Recall the direct product of nitrile reduction.
Final Logic:
- �� Reduction of –CN gives –CH₂NH₂.
- CN → CH₂NH₂
15 What is the IUPAC name of the primary amine formed when Benzamide is completely reduced with LiAlH₄?
�� Benzamide is reduced by LiAlH₄. �� Carbonyl group converts to –CH₂–. �� Product is benzylamine (IUPAC: Phenylmethanamine).
- Benzamide (C₆H₅CONH₂) undergoes reduction with LiAlH₄. Reaction: C₆H₅CONH₂ → C₆H₅CH₂NH₂ → The product C₆H₅CH₂NH₂ is commonly called benzylamine. → Its correct IUPAC name is phenylmethanamine.
- �� Option A → Benzenamine is aniline (C₆H₅NH₂).
- �� Option C → Contains an N-methyl substituent not present.
- �� Option D → Benzylamine is the common name, not the IUPAC name.
Used
- Substitution
Application:
- �� Replace amide carbonyl by methylene group.
Final Logic:
- �� Benzamide reduction gives C₆H₅CH₂NH₂.
- Benzamide → Benzylamine
16 The conversion of an amide directly into an amine utilizing LiAlH₄ is best classified chemically as:
�� LiAlH₄ is a powerful reducing agent. �� It converts the carbonyl group of an amide into a methylene group. �� The product formed is an amine.
- Lithium aluminium hydride (LiAlH₄) reduces amides to amines by converting the carbonyl carbon (C=O) into a methylene group (–CH₂–). Example: CH₃CONH₂ ⟶ CH₃CH₂NH₂ → Since hydrogen is added and the oxidation state of carbon decreases, the process is classified as a reduction reaction.
- �� Option A → Oxidation involves increase in oxidation state, which does not occur.
- �� Option C → Hydrolysis involves cleavage by water.
- �� Option D → Ammonolysis involves reaction with ammonia.
Used
- Elimination
Application:
- �� Identify the role of LiAlH₄ in organic reactions.
Final Logic:
- �� LiAlH₄ converts amides into amines through reduction.
- LiAlH₄ = Powerful Reducer
17 In the Gabriel phthalimide synthesis process:
(A) Phthalimide is treated with ethanolic KOH.
(B) A potassium salt of phthalimide is generated.
(C) The salt is subsequently heated with an alkyl halide.
(D) Alkaline hydrolysis finally yields a primary amine.
�� Phthalimide forms potassium phthalimide. �� It reacts with alkyl halides. �� Hydrolysis gives primary amines.
- Gabriel synthesis proceeds through the following steps: 1. Phthalimide + ethanolic KOH → Potassium phthalimide. 2. Potassium phthalimide + Alkyl halide → N-alkylphthalimide. 3. Alkaline hydrolysis of N-alkylphthalimide → Primary amine. → Therefore all four statements are correct.
- �� Option A → Omits the final hydrolysis step.
- �� Option B → Omits the initial KOH treatment.
- �� Option C → Omits potassium salt formation.
Used
- Option Grouping
Application:
- �� Verify each step of Gabriel synthesis sequentially.
Final Logic:
- �� All listed steps belong to Gabriel synthesis.
- KOH → Alkylation → Hydrolysis → 1° Amine
18 Which of the following compounds CANNOT be prepared using Gabriel phthalimide synthesis?
�� Gabriel synthesis prepares primary aliphatic amines. �� Aryl halides do not undergo the required nucleophilic substitution. �� Therefore aniline cannot be prepared.
- Gabriel phthalimide synthesis works through nucleophilic substitution of alkyl halides by the phthalimide anion. → Aryl halides generally do not undergo nucleophilic substitution under these conditions. → Since aniline (C₆H₅NH₂) is an aromatic primary amine, it cannot be synthesized by this method.
- �� Option A → Methanamine can be prepared.
- �� Option B → Ethanamine can be prepared.
- �� Option C → Propan-1-amine can be prepared.
Used
- Elimination
Application:
- �� Identify which compound is aromatic rather than aliphatic.
Final Logic:
- �� Gabriel synthesis fails for arylamines.
- Gabriel → Aliphatic Only
19 Identify the specific reaction type illustrated:
Amide + Br₂ + NaOH(aq) → Primary amine + Carbon loss
�� Uses Br₂ and NaOH. �� Converts amide to primary amine. �� Product contains one carbon less.
- Hoffmann bromamide degradation converts an amide into a primary amine using bromine and aqueous sodium hydroxide. General reaction: RCONH₂ + Br₂ + 4NaOH → RNH₂ + Na₂CO₃ + 2NaBr + 2H₂O → The amine formed contains one carbon atom less than the parent amide.
- �� Option A → Gabriel synthesis uses phthalimide.
- �� Option C → Sandmeyer reaction involves diazonium salts.
- �� Option D → Ammonolysis involves ammonia and alkyl halides.
Used
- Odd One Out
Application:
- �� Recognize the characteristic reagent pair Br₂/NaOH.
Final Logic:
- �� Br₂ + NaOH + amide indicates Hoffmann degradation.
- Br₂ + NaOH = Hoffmann
20 About the Hoffmann bromamide degradation:
(A) The amine formed contains one carbon more than the amide.
(B) An alkyl or aryl group explicitly migrates.
(C) Migration occurs from the carbonyl carbon to the nitrogen atom.
(D) The final amine contains one carbon less than the starting amide.
�� Rearrangement involves group migration. �� Product contains one less carbon atom. �� Carbonyl carbon is lost as carbonate/CO₂.
- In Hoffmann bromamide degradation: • An alkyl/aryl group migrates during rearrangement. • The carbonyl carbon is removed from the carbon skeleton. • The resulting primary amine contains one carbon atom less than the original amide. Thus: ✓ (B) Correct ✓ (D) Correct ✗ (A) Incorrect ✗ (C) Incorrect
- �� Option B → Statement A is incorrect.
- �� Option C → Statement C is incorrect. Migration is not described as carbonyl carbon moving to nitrogen.
- �� Option D → Both statements are incorrect.
Used
- Elimination
Application:
- �� Apply the key feature: one-carbon loss.
Final Logic:
- �� Hoffmann degradation gives a primary amine with one less carbon and involves migration.
- Hoffmann = Minus One Carbon
