Claudia Jarvis "Like Dissolves Like" Polar substances only dissolve in other polar substancesNon-polar substances only dissolve in non-polar substancesNon-polar substances can't dissolve in polar substances. Intermolecular Forces in Solution A solution is a mixture of two or more substances in a single phase. At least two substances must be mixed in order to have a solution. The substance in the smallest amount and the one that dissolves or disperses is called the SOLUTE. The substance in the larger amount is called the SOLVENT.