Question

What forces are most responsible for forming the following solids: sodium chloride, triacontane (C30H62) and 1-hexadecanol.

Answer 1

Intermolecular forces existing between molecules are solely responsible for a compound existing in the solid phase. If the magnitude of these forces are overcome by external energy, they tend to go into a liquid phase. Now, the predominant such force present in sodium chloride is the immense attractive force between positive and negative ions in the ionic salt - electrostatic interaction. Triacontane is a saturated hydrocarbon and so, in its solid state, the strongest forces existing between triacontane molecules is van der Waals forces which is a hydrophobic interaction that arises from the attraction of positively charged particles in atoms' nuclei and other atoms' negatively charged electron clouds. Finally, the intermolecular force responsible for forming a solid of 1-hexadecanol is hydrogen bonding. This arises by hydrogens attached to electronegative atoms, forming a very weak, reversible bond with other alcohol molecule's atoms with one or more available lone pairs of electrons to donate reversibly to the H atom. In this case, the hydroxyl H and hydroxyl O atoms of different 1-hexadecanol molecules form H-bonding.