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 ascertain the compound with the highest boiling point among the provided options, an assessment of the intermolecular forces present in each substance is necessary. Generally, more robust intermolecular forces correlate with elevated boiling points.

• \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_3\): Identified as butane, an alkane. Alkanes exhibit weak van der Waals (dispersion) forces owing to their non-polar characteristic, resulting in a comparatively low boiling point.
• \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{–OH}\): Identified as butanol, an alcohol. The hydroxyl group (-OH) in alcohols facilitates hydrogen bonding. Hydrogen bonds are intrinsically stronger than van der Waals forces, consequently leading to a higher boiling point.
• \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CHO}\): Identified as butanal, an aldehyde. Aldehydes possess dipole-dipole interactions stemming from the carbonyl group. These interactions are more potent than van der Waals forces but less so than hydrogen bonds.
• \(\text{H}_5\text{C}_2 - \text{O} - \text{C}_2\text{H}_5\): Identified as diethyl ether, an ether. Ethers, analogous to aldehydes, exhibit dipole-dipole interactions but do not participate in hydrogen bonding.

Consequently, butanol is anticipated to exhibit the highest boiling point due to the presence of hydrogen bonding, a potent intermolecular force.

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