Question

Find the correct order of increasing boiling point in the following given molecules: (A) n-\( C_4 H_9 OH \)
(B) n-\( C_4 H_9 NH_2 \)
(C) n-\( C_4 H_{10} \)
(D) \( C_2 H_5 NH C_2 H_5 \)

• A. C<D<B<A
• B. A<B<D<C
• C. D<C<A<B
• D. B<C<D<A

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
Boiling point depends on the strength of intermolecular forces such as Hydrogen bonding, Dipole-Dipole interactions, and Van der Waals forces.
Step 2: Detailed Explanation:
- (A) \(n\)-Butanol (\(n-C_4H_9OH\)): Contains strong O-H hydrogen bonding. Alcohol bonds are stronger than amine bonds due to the higher electronegativity of Oxygen.
- (B) \(n\)-Butylamine (\(n-C_4H_9NH_2\)): A primary amine. Contains N-H hydrogen bonding.
- (D) Diethylamine (\(C_2H_5NHC_2H_5\)): A secondary amine. It has weaker H-bonding compared to primary amines because there is only one H atom available for bonding and more steric hindrance.
- (C) \(n\)-Butane (\(n-C_4H_{10}\)): A non-polar alkane. Only weak Van der Waals (London) forces exist.
Ranking: Alkane (C) < Secondary Amine (D) < Primary Amine (B) < Alcohol (A).
Step 3: Final Answer:
The correct order of increasing boiling point is C < D < B < A.