The Board War 2023 – Chemistry Class 12 Amines Sheet
Amines
Short Answer Type Questions
1. What is the role of HNO3 in the nitrating mixture used for the nitration of benzene?
Answer: HNO3 acts as a base in the nitrating mixture and provides the electrophile NO2+ ion
for the nitration of benzene.
2. Why is the NH2 group of aniline acetylated before carrying out nitration?
Answer: NH2 group of aniline is acetylated first so that controlled nitration can occur at the
para position. If the NH2 group of aniline is not acetylated, then a mixture of ortho, meta and
para products will form.
3. What is the best reagent to convert nitrile to primary amine?
Answer: LiAlH4 and Sodium/Alcohol are the best reagents for converting nitrile to a primary
amine. The nitriles are transformed into a corresponding primary amine through reduction
4.What is Hinsberg reagent?
Answer: Hinsberg reagent is an alternative name for benzene sulfonyl chloride (C6H5SO2Cl). It
is used to detect and distinguish primary, secondary, and tertiary amines in a given sample.
5.Explain why MeNH2 is a stronger base than MeOH?
Answer: Nitrogen is less electronegative than oxygen; therefore, lone pairs of electrons on
nitrogen are readily available for donation. Hence, MeNH2 is more basic than MeOH.
6.Why is an alkylamine more basic than ammonia?
Answer: Due to electron releasing inductive effect (+1) of alkyl group, the electron density on
the nitrogen atom increases and thus, it can donate the lone pair of electrons more easily
than ammonia.
, 7. Give the IUPAC name of H2N — CH2—CH2—CH = CH2.
Answer:
IUPAC name : But-3-ene-1-amine
8.Write the structure of n-methylethanamine. (All India 2013)
Answer:
Structure of n-methylethanamine :
H3C—H2C—NH—CH2
8. Write the structure of 2-aminotoluene. (All India 2013)
Answer:
9.How may methyl bromide be preferentially converted to methyl isocyanide? (Comptt. Delhi
2013)
Answer: Carbylamine reaction:
10. Out of CH3—NH2 and (CH3)3N, which one has higher boiling point?
Answer:
CH3—NH2 has higher boiling point than (CH3)3N.
11.Give the chemical tests to distinguish between the following pairs of compounds :
(i) Methylamine and Dimethylamine
(ii) Aniline and N-methylaniline
(i) Methylamine and Dimethylamine :
By Carbylamine test: Methylamine being a primary amine gives this test but Dimethylamine
being a secondary amine does not.
Amines
Short Answer Type Questions
1. What is the role of HNO3 in the nitrating mixture used for the nitration of benzene?
Answer: HNO3 acts as a base in the nitrating mixture and provides the electrophile NO2+ ion
for the nitration of benzene.
2. Why is the NH2 group of aniline acetylated before carrying out nitration?
Answer: NH2 group of aniline is acetylated first so that controlled nitration can occur at the
para position. If the NH2 group of aniline is not acetylated, then a mixture of ortho, meta and
para products will form.
3. What is the best reagent to convert nitrile to primary amine?
Answer: LiAlH4 and Sodium/Alcohol are the best reagents for converting nitrile to a primary
amine. The nitriles are transformed into a corresponding primary amine through reduction
4.What is Hinsberg reagent?
Answer: Hinsberg reagent is an alternative name for benzene sulfonyl chloride (C6H5SO2Cl). It
is used to detect and distinguish primary, secondary, and tertiary amines in a given sample.
5.Explain why MeNH2 is a stronger base than MeOH?
Answer: Nitrogen is less electronegative than oxygen; therefore, lone pairs of electrons on
nitrogen are readily available for donation. Hence, MeNH2 is more basic than MeOH.
6.Why is an alkylamine more basic than ammonia?
Answer: Due to electron releasing inductive effect (+1) of alkyl group, the electron density on
the nitrogen atom increases and thus, it can donate the lone pair of electrons more easily
than ammonia.
, 7. Give the IUPAC name of H2N — CH2—CH2—CH = CH2.
Answer:
IUPAC name : But-3-ene-1-amine
8.Write the structure of n-methylethanamine. (All India 2013)
Answer:
Structure of n-methylethanamine :
H3C—H2C—NH—CH2
8. Write the structure of 2-aminotoluene. (All India 2013)
Answer:
9.How may methyl bromide be preferentially converted to methyl isocyanide? (Comptt. Delhi
2013)
Answer: Carbylamine reaction:
10. Out of CH3—NH2 and (CH3)3N, which one has higher boiling point?
Answer:
CH3—NH2 has higher boiling point than (CH3)3N.
11.Give the chemical tests to distinguish between the following pairs of compounds :
(i) Methylamine and Dimethylamine
(ii) Aniline and N-methylaniline
(i) Methylamine and Dimethylamine :
By Carbylamine test: Methylamine being a primary amine gives this test but Dimethylamine
being a secondary amine does not.
