Question

Which isomer of \(C_4H_9Cl\) has the lowest boiling point?

Hint:

Branched isomers generally have lower boiling points compared to their straight-chain counterparts due to weaker van der Waals forces arising from their reduced surface area.

Answer 1

The isomer of C₄H₉Cl with the lowest boiling point is tert-butyl chloride (C₄H₉Cl), also known as 2-chloro-2-methylpropane (CH₃)₃C-Cl.

This is because the high degree of branching in the tert-butyl chloride molecule reduces the surface area available for intermolecular interactions, such as Van der Waals forces. With fewer opportunities for these interactions, the molecule is easier to vaporize, leading to a lower boiling point compared to less branched isomers, such as n-butyl chloride or sec-butyl chloride.