IIT JEE Advanced 2006 Paper 1

The structures of the given compounds are as follows:

We know that the boiling point increases as molecular mass increases so IV has the least boiling point. Also, among the isomeric alcohols, para-isomer has the highest value of boiling point being symmetrical in nature; followed by meta- and then ortho-isomers.
Hence, the correct order of boiling points is IV < I < II < III.