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

The Correct Option is B

To determine which compound has the highest boiling point among the given options, we need to consider the types of intermolecular forces present in each compound. Generally, stronger intermolecular forces result in higher boiling points. 

• \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_3\): This is butane, an alkane. Alkanes have weak van der Waals (dispersion) forces due to their non-polar nature. Thus, it has a relatively low boiling point.
• \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{–OH}\): This is butanol, an alcohol. Alcohols can form hydrogen bonds due to the presence of the hydroxyl group (-OH). Hydrogen bonds are stronger than van der Waals forces, leading to a higher boiling point.
• \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CHO}\): This is butanal, an aldehyde. Aldehydes have dipole-dipole interactions due to the carbonyl group, which are stronger than van der Waals forces but weaker than hydrogen bonds.
• \(\text{H}_5\text{C}_2 - \text{O} - \text{C}_2\text{H}_5\): This is diethyl ether, an ether. Ethers have dipole-dipole interactions, similar to aldehydes, but no hydrogen bonding.

Among these, butanol will have the highest boiling point due to the presence of hydrogen bonding, which is a strong intermolecular force.

Therefore, the correct answer is \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{–OH}\).

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.