A
rule of thumb for
predicting the
solubilities of
solutes in
solvents.
In general, substances that have similar intermolecular forces have strong solute-solvent interactions and tend to form solutions.
Polar compounds dissolve in polar compounds and nonpolar compounds dissolve in nonpolar compunds.
Ergo:
Gasoline dissolves grease
Salts dissolve in water
Grease does not dissolve in water
Salt does not dissolve in gasoline