A solution is not a pure substance as it is a mixture between a solute and a solvent.
Pure substances are substances that are made up of only type of particles and have a fixed structure. In pure substances the matter cannot be separated into other kinds of matter by any physical means.
A homogenous mixture of two or more substances in relative amounts that can be varied continuously up to what is called the limit of solubility. The term solution is commonly applied to the liquid state of matter, but solutions of gases and solids are possible.
A solution cannot be a pure substance because it is made up of a homogenous mixture of solute and a solvent. Homogenous means the matter cannot be separated out and therefore a solution cannot be a pure substance.
