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)

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.