Question

Why is elemental sulfur more soluble in carbon disulfide than in water while sodium chloride is more soluble in water than in carbon disulfide?

Answer 1

Elemental Sulfur is a perfect example of a nonpolar solute. It is therefore more likely to be soluble in nonpolar solvents than in polar solvents such as water.

The Lewis structure of CS₂ suggests that this molecule is linear.

Thus, even it there is some separation of charge in the C=S double bond, the molecule would have no net dipole moment, because of its symmetry. The electronegativities of carbon (EN = 2.55) and sulfur (EN = 2.58), however, suggest that the C=S double bonds are almost perfectly covalent. CS₂ is therefore a nonpolar solvent, which should readily dissolve Elemental Sulfur.

Water and NaCl are both polar....they have positive and negative ends, so when they're together, they have a better chance of making a connection, like magnets. CS₂ is nonpolar, and dissolves better in a nonpolar solvent.