CHEMISTRY · Single correct · A Level · Chemistry · Bonding · Bonding
Problem
Hydrofluoric acid, HF, boils at 19 °C, whereas hydrogen chloride, HCl, boils at –85 °C. Which statement best accounts for the much higher boiling point of HF?
(a) HF has a higher molar mass, so stronger London dispersion forces raise its boiling point.
(b) The H–F bond itself is very strong; extra energy is needed to break these bonds when HF boils.
(c) Extensive hydrogen bonding between HF molecules requires more energy to separate them.
(d) Liquid HF partially ionizes to form H+ and F−; the strong ionic attractions increase its boiling point.