Question

If the boiling points of methoxyethane and propanol are 281 K and 370 K respectively, predict the boiling point of propanal.

(a) 273 K

(b) 281 K

(c) 322 K

(d) 370 K

This question was addressed to me in an international level competition.

This interesting question is from Aldehydes and Ketones Physical Properties topic in section Aldehydes, Ketones and Carboxylic Acids of Chemistry – Class 12

Answer 1

Correct answer is (c) 322 K

To explain I would say: The boiling point of aldehydes are higher than those of non-polar hydrocarbons of comparable molecular masses. However, their boiling points are lower than comparable alcohols, due to the absence of intermolecular hydrogen bonding.