Which of the following has the highest boiling point?

Options

A. `H_2O`
B. `HF`
C. `NH_3`
D. `H_2Te`

Answer

A

Explanation

The correct order of boiling points is `H_2OgtHFgtH_2TegtNH_3`
It may seem odd at first that the boiling point of HF is lower than that of water. Fluorine is more electronegative than oxygen, and so we would expect a stronger hydrogen bond in liquid HF than in `H_2O`. But `H_2O` is unique in that each molecule takes part in four intermolecular H bonds, and the `H_2O` molecules are, therefore, held together more strongly.