Question 1

What is the general formula for primary amines?

Accepted Answer

Primary amines contain one alkyl or aryl group bonded to nitrogen with two hydrogen atoms attached to nitrogen.

Question 2

Which of the following amines is most basic in aqueous solution?

Accepted Answer

Methylamine is most basic because the electron-donating alkyl group increases electron density on nitrogen, enhancing its ability to accept protons compared to aniline.

Question 3

What is the IUPAC name of the compound CH₃CH₂CH₂NH₂?

Accepted Answer

The IUPAC name follows the numbering from the carbon attached to nitrogen as position 1, making this compound 1-propanamine.

Question 4

Which reaction is commonly used to prepare primary amines from alkyl halides?

Accepted Answer

Gabriel phthalimide synthesis is a selective method for preparing primary amines from alkyl halides using phthalimide as a protecting group.

Question 5

Why is aniline (C₆H₅NH₂) a weaker base than methylamine (CH₃NH₂)?

Accepted Answer

The lone pair on nitrogen in aniline delocalizes into the benzene ring through resonance, reducing its availability for accepting protons and making aniline a weaker base.

Question 6

What is the general formula for primary amines?

Accepted Answer

Primary amines contain one alkyl/aryl group bonded to nitrogen with two hydrogen atoms attached.

Question 7

Which of the following amines is most basic in aqueous solution?

Accepted Answer

Aliphatic amines like methylamine are stronger bases than aromatic amines because the benzene ring delocalizes the lone pair, reducing basicity.

Question 8

Aniline reacts with bromine water to form a product. The major product is:

Accepted Answer

The NH₂ group in aniline is a strong ortho/para director and activator, causing multiple brominations to give 2,4,6-tribromoaniline.

Question 9

Which reagent is used to convert primary amines to aldehydes?

Accepted Answer

Copper(II) chloride with phenanthroline catalyzes selective oxidation of primary amines to aldehydes under mild conditions.

Question 10

The Hinsberg test distinguishes between primary, secondary, and tertiary amines using benzenesulfonyl chloride (C₆H₅SO₂Cl). A secondary amine will produce a product that is:

Accepted Answer

Secondary amines form N-substituted benzenesulfonamides that lack an N-H group, making them insoluble in aqueous alkali.

Question 11

What is the correct IUPAC name for the compound CH₃-CH₂-NH-CH₃?

Accepted Answer

The longest carbon chain is the principal group (methanamine), and the ethyl group is a substituent on nitrogen, giving N-ethylmethanamine.

Question 12

Ammonia (NH₃) acts as a nucleophile in the alkylation of alkyl halides. The major product when excess ethyl bromide reacts with ammonia is:

Accepted Answer

Successive alkylation with excess ethyl bromide converts NH₃ → EtNH₂ → Et₂NH → Et₃N → [Et₄N]⁺Br⁻ (quaternary ammonium salt).

Question 13

Which of the following statements about the basicity of amines is correct?

Accepted Answer

Tertiary aliphatic amines lack N-H hydrogen bonding losses and have three alkyl groups stabilizing the positive charge on the conjugate acid, increasing basicity.

Question 14

When aniline is treated with bromine water, the major product contains how many bromine atoms?

Accepted Answer

The amino group (-NH₂) is a strong ortho/para-directing activating group; bromine water adds at ortho and para positions, and the resulting product undergoes further bromination to give tribrominated aniline.

Question 15

Which of the following amines will show the highest boiling point?

Accepted Answer

Propylamine (CH₃CH₂CH₂NH₂) has the highest boiling point due to stronger hydrogen bonding capability as a primary amine with the longest hydrocarbon chain among the options.

Question 16

In the Hofmann degradation of primary amides, the ratio of carbon atoms in the amine product to the original amide is:

Accepted Answer

Hofmann degradation of RCONH₂ produces RNH₂ (primary amine) with loss of one carbon atom as CO₂, so the carbon ratio is (n-1):n, approaching 1:1 for large n, but exactly the amine has one fewer carbon than the amide.

Agniveer (All) Amines

Amines — Practice Questions