Question

Find the correct order of increasing boiling point in the following given molecules:

(A) n-\( C_4H_9OH \) \hspace{1cm} (B) n-\( C_4H_9NH_2 \)
(C) n-\( C_4H_{10} \) \hspace{1cm} (D) \( C_2H_5NH C_2H_5 \)

• 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:
This question asks for the comparison of boiling points based on intermolecular forces (H-bonding and Van der Waals forces).
Step 2: Detailed Explanation:
- (A) \(n\)-Butanol: Has strong O-H hydrogen bonding.
- (B) \(n\)-Butylamine: A primary amine (\(1^\circ\)). It has N-H hydrogen bonding, which is weaker than O-H bonding because O is more electronegative than N.
- (D) Diethylamine: A secondary amine (\(2^\circ\)). It has weaker H-bonding than primary amines due to fewer H atoms on N and steric hindrance.
- (C) \(n\)-Butane: A non-polar alkane with only weak London dispersion forces.
Relative strength of Intermolecular forces: Alcohol > Primary Amine > Secondary Amine > Alkane.
Increasing order of Boiling Point: C < D < B < A.
Step 3: Final Answer:
The correct order is (1).