Question

Why is there a large difference in the boiling points of butanal and $butan-1-ol?$

Answer 1

Boiling point and the factor affecting the boiling point

Boiling point: The temperature at which the vapour pressure of the liquid is equal to the external pressure.

$Boilingpoint$

$\propto Intermolecularforcesofattraction(H-bonding)$

Boiling point comparison

Butan-1-ol exists associated molecules as they undergo extensive intermolecular hydrogen bonding. To break the hydrogen bonds present between these molecules, a large amount of energy is required. Hence, the boiling point of Butan - 1 - ol is higher.

On the other hand, butanal molecules lack hydrogen bonding as no hydrogen is attached to oxygen. Thus, the butanal molecules have weak intermolecular forces between them, and it requires less energy to break this attraction.

Thus, the boiling point of $butan-1-ol$ is higher than the boiling point of butanal.