Why does sodium chloride melt ice and not sucrose?

Answer 1

Sodium Chloride is an ionic compound, thus it will break up into positive sodium ions and negative chloride ions that can break the hydrogen bonds that hold water molecules together in the solid structural lattice. Sucrose will melt water, but it will not melt it as fast because it is a covalent compound, not ionic, so it will not break hydrogen bonds as effectively as salt. However, sucrose is a polar molecule, and likes dissolve likes, so it will be dissolved by water and thus melt the ice, but it takes longer. (It's funny because I just did an experiment with melting points of iced tea ice cubes versus water ice cubes for my natural world class and our data supported this... easiest lab I've done in my career as a bio major haha)

Answer 2

If equal masses of lithium chloride and sodium chloride are used, the lithium chloride will melt more ice at equilibrium, because the lithium chloride will have more equivalents of solute as a result of its lower formula mass. The rate of melting can not be predicted from any simple principle, since the rate will depend on such factors as heat of solution of the two salts and heat transfer rates from the environment.

Answer 3

During the dissolution in water sodium chloride release heat.