Determine which salt you would use to melt ice most effectiv

Determine which salt you would use to melt ice most effectively on a mole per mole basis: lithium bromide, aluminum iodide or magnesium chloride. Explain.

Solution

A compound that yields more ions into a water solution would lower the freezing point of water more than salt. For example, magnesium chloride (MgCl₂) dissolves into three ions (one of magnesium and two of chloride) and lowers the freezing point of water more than sodium chloride.

hence answer is MgCl2 or magnesium chloride