Practicing Success
Arrange the following sets of compounds in order of their increasing boiling points. A. Pentan-1-ol B. Butan-1-ol C. Butan-2-ol D. Ethanol E. Propan-1-ol Choose the correct answer from the options given below: |
A < B < C < D < E B < C < D < E < A C < D < E < A < B D < E < C < B < A |
D < E < C < B < A |
The correct answer is option 4. D < E < C < B < A. The compounds Pentan-l-ol, butan-1-ol, butan-2-ol, ethanol, propan-1-ol belong to the alcohol family. Let us write the structure of these alcohols as shown below: With increase in the molecular weight, the boiling points of alcohols increase. Hence, butan-1-ol has higher boiling point than propan-1-ol. Similarly, pentan-1-ol has higher boiling point than butan-1-ol. And Propan-1-ol has higher boiling point than ethanol. Hence, the increasing order of the boiling points of alcohols is ethanol < propan-1-ol < butan-1-ol < pentan-1-ol. With increase in the branching of alkyl groups, the boiling point of alcohols decreases. Thus, butan-2-ol has lower boiling point than butan-1-ol. The increasing order of the boiling points of given alcohols is ethanol < propan-1-ol < butan-2-ol < butan-1-ol < pentan-1-ol. |