Intermolecular Forces (Edexcel International A Level Chemistry)

This question is about the forces between molecules and ions.

Some data for three small molecules are shown.

Molecule	Mr	Boiling temperature / °C
Fluorine	38.0	−188
Hydrogen chloride	36.5	−85
Methanol	32.0	65

Explain the large variation in boiling temperatures, given the small range in M_r values.

Detailed descriptions of the forces involved are not required.

Calcium chloride is soluble in water.

Explain why bromine is a liquid but iodine is a solid at room temperature.

Detailed explanations of the forces involved are not required.