Question

Which compound has the highest boiling point? A. (CH3)2CHCH2COOCH3 B. CH3CH2CH2CH2CH2COOH C. (CH3)2CHCH2CH2CH2OH D. CH3(CH2)6CH3 E. All of the compounds above have the same boiling point.

Answer 1

Among the four given compounds the carboxylic acid CH3CH2CH2CH2CH2COOH has the highest boiling point. Carboxylic acid possesses intermolecular H- bonding and also Van der Waals dispersion forces among the molecules and dipole dipole interaction. Due to these forces the molecules are very strongly connected with each other and thus the boiling point is highest for the compound.

On the other hand compound A has only van der Waals and dipole dipole interaction, compound C the alcohol has intermolecular H bonding, compound D has only weak van der Waals interaction. Order of increasing boiling point of the compound is as follows - D<A<C<B.

So, the correct answer is option B.