CGPET 2011 Solved Paper

For isomeric alcohols, the boiling points decrease in the order
Primary > secondary > tertiary
It is due to the fact that surface area decreases with branching and therefore van der Waals' force decreases.
Further, ethers have low boiling point, lower than that of isomeric alcohols. Hence, 1-methoxypropane has the lowest boiling point among the given compounds.