Question

The correct order of boiling point for primary $(1^{\circ})$ , secondary $(2^{\circ})$ and tertiary $(3^{\circ})$ alcohols is

• A. $1^{\circ} > 2^{\circ} > 3^{\circ}$
• B. $3^{\circ} > 2^{\circ} > 1^{\circ}$
• C. $2^{\circ} > 1^{\circ} > 3^{\circ}$
• D. $2^{\circ} > 3^{\circ} > 1^{\circ}$

Answer 1

Answer: (A)

$1^{\circ} > 2^{\circ} > 3^{\circ}$

Answer 2

Alcohols with same molecular weight ate expected to have almost same boiling point, however two more factors other than molecular weight are important; they are namely H-bonding and surface area of molecule. Both these factors are least in $3^\circ$ alcohols and maximum in $1^\circ$ alcohols. Hence, $3^\circ$ alcohols have least boiling point while $1^\circ$ alcohols have maximum boiling point.