Question

Which among the following has highest boiling point?

• A. $\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_3$
• B. $\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{–OH}$
• C. $\text{CH}_3\text{CH}_2\text{CH}_2\text{CHO}$
• D. $\text{H}_5\text{C}_2 - \text{O} - \text{C}_2\text{H}_5$

Answer 1

Answer: (B)

$\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{–OH}$

Answer 2

The boiling point of a compound depends on various factors such as molecular weight, type of bonding, and intermolecular forces. In this case, let’s analyze the given options:
Option (1) CH$_3$CH$_2$CH$_2$CH$_3$ (Butane): This is a hydrocarbon with weak Van der Waals forces. It has a relatively low boiling point due to the absence of hydrogen bonding.
Option (2) CH$_3$CH$_2$CH$_2$CH$_2$OH (Butanol): This compound contains an --OH (hydroxyl) group, which allows for hydrogen bonding between molecules. Hydrogen bonding significantly increases the boiling point compared to compounds with only Van der Waals interactions.
Option (3) CH$_3$CH$_2$CH$_2$CHO (Butanal): This compound has a carbonyl group (C=O), leading to dipole-dipole interactions. However, these interactions are weaker than the hydrogen bonding present in alcohols.
Option (4) C$_2$H$_5$OC$_2$H$_5$ (Diethyl ether): This compound contains an ether linkage, resulting in weak dipole-dipole interactions, but it lacks hydrogen bonding.
Conclusion: Among the given compounds, CH$_3$CH$_2$CH$_2$CH$_2$OH (butanol) has the highest boiling point due to the presence of strong intermolecular hydrogen bonding.