CUET UG Chemistry Booster Test - 2 Fundamentals of Amines -

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CUET UG Chemistry Booster Test - 2 Fundamentals of Amines

⏱️ 30 Minutes

❓ 20 Questions

📌 Answers are locked once submitted — results and explanations appear at the end.

CUET UG Chemistry Booster Test - 2 Fundamentals of Amines

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QUESTION 1 OF 20

Statements regarding the molecular foundation of amines:
(A) Nitrogen in amines is trivalent.
(B) Nitrogen in amines is pentavalent.
(C) Amines are considered derivatives of ammonia.
(D) Amines contain no unshared pair of electrons.

Answer Review

1 Statements regarding the molecular foundation of amines:
(A) Nitrogen in amines is trivalent.
(B) Nitrogen in amines is pentavalent.
(C) Amines are considered derivatives of ammonia.
(D) Amines contain no unshared pair of electrons.

A A, B

B A, C

C C, D

D B, D

💡 Short Explanation

�� Nitrogen in amines forms three covalent bonds. �� Amines are derived from ammonia. �� Nitrogen possesses one lone pair of electrons.

✅ Correct Answer Explanation

Amines are derivatives of ammonia formed by replacing one or more hydrogen atoms with alkyl or aryl groups. Nitrogen in amines is trivalent because it forms three sigma bonds and retains one unshared pair of electrons. → Statement A is correct. → Statement C is correct.

❓ Why Other Options Are Incorrect

�� Option B → Nitrogen in ordinary amines is not pentavalent.
�� Option D → Amines contain a lone pair of electrons on nitrogen.

🎯 Strategy

Used

Option Grouping

Application:

�� Verify each statement using the basic structure of amines.

Final Logic:

�� Only A and C correctly describe the molecular nature of amines.

🧠 Memory Trick

Amines = NH₃ Derivatives with Lone Pair

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Introduction to Amines

2 Identify the structural outcome when a nucleophilic substitution reaction completely replaces all three hydrogen atoms of an ammonia molecule with methyl groups:

A Primary aliphatic amine

B Secondary aliphatic amine

C Tertiary aliphatic amine

D Quaternary ammonium salt

💡 Short Explanation

�� Three hydrogen atoms are replaced. �� Product formed is trimethylamine. �� Trimethylamine is a tertiary amine.

✅ Correct Answer Explanation

Complete replacement of all three hydrogen atoms of ammonia by methyl groups gives: NH₃ → (CH₃)₃N This compound is trimethylamine, which belongs to the class of tertiary aliphatic amines because three alkyl groups are attached to nitrogen.

❓ Why Other Options Are Incorrect

�� Option A → Only one hydrogen replacement occurs.
�� Option B → Only two hydrogen replacements occur.
�� Option D → Requires four groups attached to nitrogen and a positive charge.

🎯 Strategy

Used

Substitution

Application:

�� Count the number of substituted hydrogen atoms.

Final Logic:

�� Three substitutions correspond to a tertiary amine.

🧠 Memory Trick

3 CH₃ Groups = 3° Amine

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Classification of Amines

📄 Passage

Amines constitute an important class of organic compounds derived by replacing one or more hydrogen atoms of ammonia molecule by alkyl/aryl group(s). In nature, they occur among proteins, vitamins, alkaloids and hormones. Synthetic examples include polymers, dye stuffs and drugs. Two biologically active compounds, namely adrenaline and ephedrine, both containing secondary amino group, are used to increase blood pressure. Novocain, a synthetic amino compound, is used as an anaesthetic in dentistry. Benadryl, a well known antihistaminic drug also contains tertiary amino group.

Based on the passage, which biologically active natural compounds are specifically noted for increasing blood pressure due to their secondary amino group?

A Proteins and vitamins

B Novocain and Benadryl

C Alkaloids and hormones

D Adrenaline and ephedrine

💡 Short Explanation

�� Both compounds contain secondary amino groups. �� Both are biologically active compounds. �� Both are used to increase blood pressure.

✅ Correct Answer Explanation

The passage explicitly states that adrenaline and ephedrine contain secondary amino groups and are used to increase blood pressure. Therefore, they are the correct answer.

❓ Why Other Options Are Incorrect

�� Option A → Mentioned as natural sources but not specifically linked to blood pressure increase.
�� Option B → These are synthetic drugs with different uses.
�� Option C → General categories, not specific compounds identified in the passage.

🎯 Strategy

Used

Contextual/Tonal Matching

Application:

�� Locate the exact statement from the passage.

Final Logic:

�� The passage directly identifies adrenaline and ephedrine.

🧠 Memory Trick

A & E Raise BP

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Biologically Important Amines

📄 Passage

Based on the passage, identify the specific structural type of the amino group present in the synthetic antihistaminic drug Benadryl:

A Primary amino group

B Secondary amino group

C Tertiary amino group

D Quaternary amino group

💡 Short Explanation

�� Benadryl is an antihistaminic drug. �� The passage explicitly mentions its amino group type. �� It contains a tertiary amino group.

✅ Correct Answer Explanation

The passage clearly states that Benadryl contains a tertiary amino group. Therefore, Benadryl is classified as a tertiary amine-containing drug.

❓ Why Other Options Are Incorrect

�� Option A → Not stated in the passage.
�� Option B → Secondary amino group belongs to adrenaline and ephedrine.
�� Option D → Benadryl is not a quaternary ammonium compound.

🎯 Strategy

Used

Contextual/Tonal Matching

Application:

�� Extract the explicitly stated information.

Final Logic:

�� The passage directly identifies Benadryl as containing a tertiary amino group.

🧠 Memory Trick

Benadryl = Tertiary

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Biologically Important Amines

List 1 (Amine Characteristics)	List 2 (Corresponding Feature)
1. Nitrogen valency	a. Pyramidal
2. Nitrogen hybridisation	b. Trivalent
3. Fundamental geometry	c. Unshared electron pair
4. Fourth orbital occupancy	d. sp³

A 1-b, 2-d, 3-a, 4-c

B 1-d, 2-a, 3-b, 4-c

C 1-a, 2-b, 3-c, 4-d

D 1-b, 2-c, 3-d, 4-a

💡 Short Explanation

�� Nitrogen is trivalent. �� Nitrogen is sp³ hybridised. �� The fourth orbital contains a lone pair.

✅ Correct Answer Explanation

Nitrogen in amines is trivalent and sp³ hybridised. The molecular geometry is pyramidal because one hybrid orbital contains an unshared pair of electrons. Correct matching: → 1-b → 2-d → 3-a → 4-c

❓ Why Other Options Are Incorrect

�� Option B → Hybridisation and geometry are mismatched.
�� Option C → Multiple characteristics are incorrectly assigned.
�� Option D → Fourth orbital occupancy is incorrectly matched.

🎯 Strategy

Used

Option Grouping

Application:

�� Match the known structural features one by one.

Final Logic:

�� All four standard properties correspond only to Option A.

🧠 Memory Trick

Tri–sp³–Pyramid–Lone Pair

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Structure of Amines

6 Why do amines adopt a pyramidal shape rather than a planar geometry?

A Because the nitrogen is sp² hybridised

B Because of the repulsive forces of the three C-N bonds alone

C Because the sp³ hybridisation includes three bond pairs and one unshared electron pair

D Because the carbon atoms strictly force a 120° angle

💡 Short Explanation

�� Nitrogen in amines is sp³ hybridised. �� One hybrid orbital contains a lone pair. �� The presence of the lone pair results in a pyramidal geometry.

✅ Correct Answer Explanation

In amines, nitrogen is sp³ hybridised and possesses three bond pairs along with one unshared pair of electrons. According to VSEPR theory, the electron pair geometry is tetrahedral, but because one position is occupied by a lone pair, the observed molecular geometry becomes pyramidal. The lone pair exerts greater repulsion than bond pairs, causing the characteristic pyramidal shape.

❓ Why Other Options Are Incorrect

�� Option A → Nitrogen in amines is sp³ hybridised, not sp² hybridised.
�� Option B → Bond pair repulsions alone do not explain the pyramidal geometry.
�� Option D → A 120° angle is associated with trigonal planar geometry, not amines.

🎯 Strategy

Used

Elimination

Application:

�� Eliminate options inconsistent with the known hybridisation and geometry of amines.

Final Logic:

�� Three bond pairs and one lone pair on sp³ nitrogen produce a pyramidal shape.

🧠 Memory Trick

sp³ + Lone Pair = Pyramid

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Structure and Geometry of Amines

7 Arrange the following in increasing order of the number of C–N overlaps present in their core structure:
(A) Ammonia
(B) Methanamine
(C) N-Methylethanamine
(D) N,N-Dimethylmethanamine

A (A), (B), (C), (D)

B (D), (C), (B), (A)

C (B), (C), (D), (A)

D (A), (D), (C), (B)

💡 Short Explanation

�� Ammonia contains no C–N overlap. �� Primary amines contain one C–N bond. �� Secondary and tertiary amines contain two and three C–N bonds respectively.

✅ Correct Answer Explanation

Number of C–N overlaps: → NH₃ = 0 C–N overlaps → CH₃NH₂ (Methanamine) = 1 C–N overlap → N-Methylethanamine = 2 C–N overlaps → N,N-Dimethylmethanamine = 3 C–N overlaps Thus, the increasing order is: NH₃ < Methanamine < N-Methylethanamine < N,N-Dimethylmethanamine or (A), (B), (C), (D)

❓ Why Other Options Are Incorrect

�� Option B → Gives decreasing order.
�� Option C → Ammonia should appear first because it has zero C–N overlaps.
�� Option D → Tertiary amine cannot have fewer C–N overlaps than primary amine.

🎯 Strategy

Used

Substitution

Application:

�� Write the structures and count C–N sigma bonds.

Final Logic:

�� 0 < 1 < 2 < 3 C–N overlaps gives A → B → C → D.

🧠 Memory Trick

0 → 1 → 2 → 3 C–N Bonds

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Bonding and Structure of Amines

8 The unit value representing the exact number of unshared electron pairs on the nitrogen atom in a primary aliphatic amine is:

A 0

B 1

C 2

D 3

💡 Short Explanation

�� Nitrogen in amines is trivalent. �� Three orbitals participate in bond formation. �� One orbital contains a lone pair.

✅ Correct Answer Explanation

A primary aliphatic amine has the general formula RNH₂. Nitrogen forms three sigma bonds and retains one unshared pair of electrons. This lone pair is responsible for the basic nature of amines and occupies the fourth sp³ hybrid orbital. Therefore, the number of unshared electron pairs on nitrogen is exactly one.

❓ Why Other Options Are Incorrect

�� Option A → Nitrogen always contains a lone pair in ordinary amines.
�� Option C → Nitrogen does not possess two lone pairs in amines.
�� Option D → Three lone pairs would not allow the formation of three covalent bonds.

🎯 Strategy

Used

Elimination

Application:

�� Count the electron pairs around nitrogen using its valency and hybridisation.

Final Logic:

�� Three bonds and one lone pair mean nitrogen has exactly one unshared pair.

🧠 Memory Trick

Amine N = One Lone Pair

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Lone Pair and Hybridisation

9 Regarding the bond angles in amines:
(A) The C–N–E angle is less than 109.5°.
(B) The C–N–E angle is exactly 109.5°.
(C) Repulsive forces from the unshared pair of electrons compress the angle.
(D) Repulsive forces from the bond pairs expand the angle beyond 110°.

A B, D

B A, C

C A, D

D C, D

💡 Short Explanation

�� Amines possess a lone pair on nitrogen. �� Lone pair-bond pair repulsion is stronger than bond pair-bond pair repulsion. �� The bond angle becomes less than 109.5°.

✅ Correct Answer Explanation

The ideal tetrahedral angle is 109.5°. However, in amines, nitrogen contains a lone pair of electrons. Lone pair-bond pair repulsion is stronger than bond pair-bond pair repulsion, which pushes the bonded atoms closer together and decreases the C–N–E angle. Thus: ✓ Statement A is correct. ✓ Statement C is correct.

❓ Why Other Options Are Incorrect

�� Option A → Statement B is incorrect because the angle is less than 109.5°.
�� Option C → Statement D is incorrect because bond pairs do not expand the angle beyond 110°.
�� Option D → Statement D is incorrect for the same reason.

🎯 Strategy

Used

Option Grouping

Application:

�� Verify each statement using VSEPR theory.

Final Logic:

�� Only A and C correctly explain bond angles in amines.

🧠 Memory Trick

Lone Pair → Smaller Angle

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Bond Angles in Amines

10 In trimethylamine, the C–N–C bond angle is observed to be 108°. This specific deviation from the standard tetrahedral geometry is primarily an application of:

A Electronegativity differences between carbon and hydrogen

B Lone pair-bond pair repulsion compressing the angle

C Hydrogen bonding between methyl groups

D sp² hybridisation geometry

💡 Short Explanation

�� Trimethylamine contains a lone pair on nitrogen. �� Lone pair repulsion is stronger than bond pair repulsion. �� The bond angle decreases from 109.5° to about 108°.

✅ Correct Answer Explanation

Trimethylamine contains sp³ hybridised nitrogen with one lone pair. According to VSEPR theory, the lone pair occupies more space than bonding pairs and exerts stronger repulsive forces. This compresses the C–N–C bond angle from the ideal tetrahedral value of 109.5° to approximately 108°.

❓ Why Other Options Are Incorrect

�� Option A → Electronegativity differences are not the primary reason for the bond-angle reduction.
�� Option C → Hydrogen bonding does not occur between methyl groups.
�� Option D → Nitrogen is sp³ hybridised, not sp² hybridised.

🎯 Strategy

Used

Elimination

Application:

�� Compare all options with VSEPR theory and the known structure of trimethylamine.

Final Logic:

�� Lone pair-bond pair repulsion is directly responsible for the observed bond angle reduction.

🧠 Memory Trick

Lone Pair Shrinks 109.5° → 108°

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Geometry and Bond Angles of Amines

List 1 (Substitution Action)	List 2 (Resulting Class)
1. Replacing one H in NH₃	a. Tertiary amine
2. Replacing two H in NH₃	b. Secondary amine
3. Replacing three H in NH₃	c. Primary amine
4. Replacing one H in RNH₂	d. Secondary amine

A 1-a, 2-b, 3-c, 4-d

B 1-c, 2-b, 3-a, 4-d

C 1-b, 2-c, 3-d, 4-a

D 1-c, 2-d, 3-a, 4-b

💡 Short Explanation

�� One substitution in NH₃ gives a primary amine. �� Two substitutions give a secondary amine. �� Three substitutions give a tertiary amine.

✅ Correct Answer Explanation

Classification of amines depends on the number of hydrogen atoms replaced. → NH₃ → RNH₂ = Primary amine → NH₃ → R₂NH = Secondary amine → NH₃ → R₃N = Tertiary amine → Replacing one hydrogen in RNH₂ produces R₂NH, a secondary amine. Correct matching: 1-c, 2-b, 3-a, 4-d

❓ Why Other Options Are Incorrect

�� Option A → Primary and tertiary amines are interchanged.
�� Option C → Multiple substitution classes are mismatched.
�� Option D → Although d and b both represent secondary amine, the official matching follows Option B.

🎯 Strategy

Used

Option Grouping

Application:

�� Count hydrogen substitutions step-by-step.

Final Logic:

�� 1H → Primary, 2H → Secondary, 3H → Tertiary.

🧠 Memory Trick

1-2-3 Replacements = 1°-2°-3°

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Classification of Amines

12 The accepted IUPAC name for the simplest arylamine, where one hydrogen of ammonia is replaced by a benzene ring (C₆H₅NH₂), is:

A Phenylamine

B Benzenamine

C N-Phenylmethanamine

D Cyclohexanamine

💡 Short Explanation

�� C₆H₅NH₂ is the simplest aromatic amine. �� The accepted IUPAC name is benzenamine. �� Aniline is its common name.

✅ Correct Answer Explanation

The compound C₆H₅NH₂ consists of an amino group attached directly to a benzene ring. According to IUPAC nomenclature, the accepted name is Benzenamine. The compound is also widely known by its retained common name, Aniline.

❓ Why Other Options Are Incorrect

�� Option A → Phenylamine is descriptive but not the preferred IUPAC name.
�� Option C → Does not represent the structure correctly.
�� Option D → Cyclohexanamine contains a cyclohexane ring, not benzene.

🎯 Strategy

Used

Conceptual/Tonal Matching

Application:

�� Recall the preferred IUPAC name of aniline.

Final Logic:

�� C₆H₅NH₂ is officially named benzenamine.

🧠 Memory Trick

Benzene + NH₂ = Benzenamine

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Nomenclature of Aromatic Amines

13 When an alkyl halide undergoes ammonolysis with a large excess of ammonia, the major product isolated is a:

A Primary amine

B Secondary amine

C Tertiary amine

D Quaternary ammonium salt

💡 Short Explanation

�� Excess ammonia suppresses further alkylation. �� Primary amine is formed preferentially. �� This is the standard ammonolysis method.

✅ Correct Answer Explanation

During ammonolysis, an alkyl halide reacts with ammonia to produce a primary amine. If ammonia is present in large excess, it minimizes further reactions of the primary amine with alkyl halide. Therefore, the major product obtained is a primary amine. General reaction: RX + NH₃ → RNH₂

❓ Why Other Options Are Incorrect

�� Option B → Forms upon further alkylation of a primary amine.
�� Option C → Requires multiple alkylation steps.
�� Option D → Requires complete alkylation and formation of a positively charged nitrogen center.

🎯 Strategy

Used

Contextual/Tonal Matching

Application:

�� Recall the role of excess ammonia in ammonolysis.

Final Logic:

�� Excess NH₃ favors formation of primary amines.

🧠 Memory Trick

Excess NH₃ → Primary Amine

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Preparation of Amines by Ammonolysis

14 Identify the structural amine type for the compound 2-Methylaniline (o-Toluidine):

A Primary aliphatic amine

B Primary aromatic amine

C Secondary aromatic amine

D Tertiary aromatic amine

💡 Short Explanation

�� The amino group is attached directly to a benzene ring. �� Nitrogen is attached to only one carbon-containing group. �� Therefore it is a primary aromatic amine.

✅ Correct Answer Explanation

In 2-Methylaniline (o-Toluidine), the amino group (–NH₂) is directly attached to an aromatic benzene ring. Since only one hydrogen atom of ammonia has been replaced by an aryl group, it is classified as a primary aromatic amine.

❓ Why Other Options Are Incorrect

�� Option A → It is aromatic, not aliphatic.
�� Option C → Secondary aromatic amines contain two carbon-containing groups attached to nitrogen.
�� Option D → Tertiary aromatic amines contain three carbon-containing groups attached to nitrogen.

🎯 Strategy

Used

Substitution

Application:

�� Identify the ring type and count substitutions on nitrogen.

Final Logic:

�� Aromatic ring + NH₂ group = Primary aromatic amine.

🧠 Memory Trick

Ar–NH₂ = Primary Aromatic

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Aromatic Amines

15 Characteristics of secondary amines:
(A) Formed by replacing one hydrogen of a primary amine with an alkyl group.
(B) Can be represented by the formula R-NHR'.
(C) Do not contain any hydrogen atoms attached to the nitrogen.
(D) The IUPAC naming uses the locant 'N' to designate the substituent.

A A, B, D

B A, C, D

C B, C

D A, B, C, D

💡 Short Explanation

�� Secondary amines contain two carbon-containing groups attached to nitrogen. �� One hydrogen atom remains attached to nitrogen. �� N-locants are used in IUPAC nomenclature.

✅ Correct Answer Explanation

Secondary amines are obtained when two hydrogen atoms of ammonia are replaced by alkyl/aryl groups. ✓ Statement A is correct. ✓ Statement B is correct because the general formula is R–NHR'. ✓ Statement D is correct because N is used to indicate substitution on nitrogen. ✗ Statement C is incorrect because secondary amines still possess one hydrogen atom attached to nitrogen.

❓ Why Other Options Are Incorrect

�� Option B → Statement C is incorrect.
�� Option C → Statement C is incorrect and Statement A is omitted.
�� Option D → Includes Statement C, which is false.

🎯 Strategy

Used

Option Grouping

Application:

�� Verify each statement using the general structure of secondary amines.

Final Logic:

�� Only A, B and D correctly describe secondary amines.

🧠 Memory Trick

Secondary = Two Groups, One H Left

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Secondary Amines and Nomenclature

16 Arrange the following amines in decreasing order of the number of hydrogen atoms directly attached to the central nitrogen atom:
(A) Methanamine
(B) N,N-Dimethylmethanamine
(C) N-Methylethanamine
(D) Ammonia

A (D), (A), (C), (B)

B (A), (B), (C), (D)

C (D), (C), (B), (A)

D (B), (C), (A), (D)

💡 Short Explanation

�� Ammonia has three N–H bonds. �� Methanamine has two N–H bonds. �� Secondary amine has one N–H bond, and tertiary amine has none.

✅ Correct Answer Explanation

The number of hydrogen atoms directly attached to nitrogen is: → Ammonia (NH₃) = 3 hydrogens → Methanamine (CH₃NH₂) = 2 hydrogens → N-Methylethanamine (CH₃CH₂NHCH₃) = 1 hydrogen → N,N-Dimethylmethanamine [(CH₃)₃N] = 0 hydrogens Therefore, the decreasing order is: (D), (A), (C), (B)

❓ Why Other Options Are Incorrect

�� Option B → Does not start with ammonia, which has the highest number of N–H bonds.
�� Option C → Places secondary and tertiary amines before primary amine incorrectly.
�� Option D → Starts with tertiary amine, which has zero N–H bonds.

🎯 Strategy

Used

Substitution

Application:

�� Write the structure of each amine and count N–H bonds.

Final Logic:

�� 3 > 2 > 1 > 0 gives D → A → C → B.

🧠 Memory Trick

NH₃: 3H, 1°: 2H, 2°: 1H, 3°: 0H

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Classification of Amines

17 What is the IUPAC name for the tertiary amine (CH₃CH₂)₃N?

A Triethylamine

B N,N-Diethylethanamine

C N-Ethyl-N-methylethanamine

D N,N-Dimethylbutan-1-amine

💡 Short Explanation

�� The compound has three ethyl groups attached to nitrogen. �� One ethyl group is treated as the parent ethanamine. �� The remaining two ethyl groups are named as N,N-diethyl substituents.

✅ Correct Answer Explanation

(CH₃CH₂)₃N is a tertiary amine containing three ethyl groups attached to nitrogen. In IUPAC nomenclature, the longest alkyl group attached to nitrogen is chosen as the parent amine. Here, one ethyl group gives the parent name ethanamine, while the other two ethyl groups are treated as substituents on nitrogen. Therefore, the IUPAC name is N,N-Diethylethanamine.

❓ Why Other Options Are Incorrect

�� Option A → Triethylamine is the common name, not the IUPAC name.
�� Option C → This would contain one ethyl and one methyl substituent on nitrogen, not three ethyl groups.
�� Option D → This represents a different carbon skeleton and substituent pattern.

🎯 Strategy

Used

Substitution

Application:

�� Identify the parent alkylamine and name remaining groups as N-substituents.

Final Logic:

�� Three ethyl groups on nitrogen give N,N-Diethylethanamine.

🧠 Memory Trick

Triethylamine = N,N-Diethylethanamine

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Nomenclature of Tertiary Amines

18 A tertiary amine of the type RNR'R'' signifies that:

A Three different halogens are attached to nitrogen.

B Three different alkyl or aryl groups have replaced all hydrogen atoms on the ammonia nitrogen.

C The nitrogen atom is sp² hybridised.

D The molecule acts as an acid.

💡 Short Explanation

�� Tertiary amines have three carbon-containing groups attached to nitrogen. �� No hydrogen remains attached to nitrogen. �� R, R′ and R″ may be same or different alkyl/aryl groups.

✅ Correct Answer Explanation

A tertiary amine has the general formula R₃N or RNR′R″. This means all three hydrogen atoms of ammonia have been replaced by alkyl or aryl groups. When R, R′ and R″ are different, it is a mixed tertiary amine.

❓ Why Other Options Are Incorrect

�� Option A → R groups represent alkyl or aryl groups, not halogens.
�� Option C → Nitrogen in amines is generally sp³ hybridised.
�� Option D → Amines are basic due to the lone pair on nitrogen, not acidic.

🎯 Strategy

Used

Elimination

Application:

�� Eliminate statements inconsistent with amine structure and properties.

Final Logic:

�� RNR′R″ clearly represents nitrogen bonded to three alkyl/aryl groups.

🧠 Memory Trick

Tertiary = Three R Groups

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Tertiary Amines

List 1 (Amine Name)	List 2 (Classification)
1. N-Methylethanamine	a. Mixed secondary amine
2. N,N-Dimethylmethanamine	b. Simple tertiary amine
3. Diethylamine	c. Simple secondary amine
4. N,N-Diethylbutan-1-amine	d. Mixed tertiary amine

A 1-a, 2-b, 3-c, 4-d

B 1-b, 2-a, 3-d, 4-c

C 1-c, 2-d, 3-a, 4-b

D 1-a, 2-c, 3-b, 4-d

💡 Short Explanation

�� N-Methylethanamine is a mixed secondary amine. �� N,N-Dimethylmethanamine is a simple tertiary amine. �� Diethylamine is a simple secondary amine.

✅ Correct Answer Explanation

Classification depends on whether the groups attached to nitrogen are identical or different. → N-Methylethanamine has methyl and ethyl groups attached to nitrogen, so it is a mixed secondary amine. → N,N-Dimethylmethanamine has three methyl groups attached to nitrogen, so it is a simple tertiary amine. → Diethylamine has two ethyl groups attached to nitrogen, so it is a simple secondary amine. → N,N-Diethylbutan-1-amine has ethyl and butyl groups attached to nitrogen, so it is a mixed tertiary amine. Correct matching: 1-a, 2-b, 3-c, 4-d

❓ Why Other Options Are Incorrect

�� Option B → N-Methylethanamine is not a simple tertiary amine, and Diethylamine is not a mixed tertiary amine.
�� Option C → Multiple classifications are interchanged.
�� Option D → N,N-Dimethylmethanamine is incorrectly classified as simple secondary instead of simple tertiary.

🎯 Strategy

Used

Option Grouping

Application:

�� First identify simple vs mixed based on identical or different substituent groups.

Final Logic:

�� Same groups = simple; different groups = mixed; number of groups decides secondary or tertiary.

🧠 Memory Trick

Same = Simple, Different = Mixed

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Simple and Mixed Amines

20 Identify the classification type of the amine formed when N-Methylmethanamine reacts with ethyl chloride to form a tertiary amine:

A Simple primary amine

B Simple tertiary amine

C Mixed tertiary amine

D Mixed secondary amine

💡 Short Explanation

�� N-Methylmethanamine is a secondary amine. �� Reaction with ethyl chloride adds an ethyl group to nitrogen. �� The final tertiary amine has different alkyl groups.

✅ Correct Answer Explanation

N-Methylmethanamine is dimethylamine, having two methyl groups attached to nitrogen. When it reacts with ethyl chloride, an ethyl group is introduced on nitrogen, forming an amine with two methyl groups and one ethyl group. Since nitrogen is attached to three alkyl groups, it is a tertiary amine. Since the groups are not all identical, it is a mixed tertiary amine.

❓ Why Other Options Are Incorrect

�� Option A → The product is not primary because nitrogen has three alkyl groups.
�� Option B → It is not simple because all attached alkyl groups are not identical.
�� Option D → It is not secondary because nitrogen has three alkyl groups after reaction.

🎯 Strategy

Used

Substitution

Application:

�� Add the ethyl group to the secondary amine and classify the final structure.

Final Logic:

�� Two methyl groups + one ethyl group on nitrogen = mixed tertiary amine.

🧠 Memory Trick

3 Groups + Different = Mixed Tertiary

📚 Class XII – Chemistry Part II – Chapter: Amines – Topic: Simple and Mixed Tertiary Amines

CUET UG Chemistry Booster Test – 2 Fundamentals of Amines

CUET UG Chemistry Booster Test - 2 Fundamentals of Amines

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