Question 1 of 20intermediate🔧 ApplyLong Answer5 marks

(i) Write structures of different isomeric amines corresponding to the molecular formula, C₄H₁₁N. (ii) Write IUPAC names of all the isomers. (iii) What type of isomerism is exhibited by different pairs of amines?

(i)
Answer

The eight isomeric amines with molecular formula C₄H₁₁N are:

Primary Amines (4):

  1. CH₃CH₂CH₂CH₂NH₂
  2. CH₃CH₂CH(NH₂)CH₃
  3. (CH₃)₂CHCH₂NH₂
  4. (CH₃)₃CNH₂

Secondary Amines (3): 5. CH₃CH₂CH₂NHCH₃ 6. CH₃CH(NHCH₃)CH₃ 7. (CH₃CH₂)₂NH

Tertiary Amine (1): 8. CH₃CH₂N(CH₃)₂

(ii)
Answer

IUPAC Names:

Primary Amines:

  1. Butan-1-amine
  2. Butan-2-amine
  3. 2-Methylpropan-1-amine
  4. 2-Methylpropan-2-amine

Secondary Amines: 5. N-Methylpropan-1-amine 6. N-Methylpropan-2-amine 7. N-Ethylethanamine

Tertiary Amine: 8. N,N-Dimethylethanamine

(iii)
Answer

Types of Isomerism:

  1. Chain Isomerism: Exhibited between butan-1-amine and 2-methylpropan-1-amine (different carbon chain arrangements).

  2. Position Isomerism: Exhibited between butan-1-amine and butan-2-amine (position of –NH₂ group differs).

  3. Metamerism: Exhibited between secondary amines like N-methylpropan-1-amine and N-ethylethanamine (different alkyl groups on either side of –NH–).

  4. Functional Isomerism: Exhibited among primary, secondary and tertiary amines (same molecular formula but different functional groups).

Explanation

The molecular formula C₄H₁₁N corresponds to saturated amines. These can be classified as primary (RNH₂), secondary (R₂NH), and tertiary (R₃N) amines. Primary amines show chain and position isomerism. Secondary amines exhibit metamerism. All three classes exhibit functional isomerism among themselves as they have the same molecular formula but different functional groups.

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