Pure substances have fixed melting or boiling points.
Pure substances consists of only one kind of matter. All the particles of a pure substance are alike. It has a definite composition and similar properties. This is the reason that pure substances have fixed melting or boiling points.
Solution Electricity Neither Has Mass Nor It Occupies Space. Beside It Can Not Be Seen by Our Eyes. this is Why Electricity is Not Considered Matter. Concept: Change of State of the Matter on the Basis of Inter Particle Space and Inter Particle Attraction and Collision.