Question

Given below are two statements :
Statement I : The boiling point of three isomeric pentanes follows the order
n-pentane > isopentane > neopentane
Statement II : When branching increases, the molecule attains a shape of sphere. This results in smaller surface area for contact, due to which the intermolecular forces between the spherical molecules are weak, thereby lowering the boiling point.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both Statement I and Statement II are correct.
• B. Both Statement I and Statement II are incorrect.
• C. Statement I is correct but Statement II is incorrect.
• D. Statement I is incorrect but Statement II is correct.

Answer 1

Answer: (A)

Both Statement I and Statement II are correct.

Answer 2

1. The boiling point decreases with increased branching because branched-chain alkanes have less surface area for intermolecular forces.
2. Statement II accurately explains the phenomenon of lower boiling points in branched isomers.