Matter with uniform properties and a fixed composition is called a phase.
Types of Phase System
There are two types of phase.
(i) Homogeneous Phase System (Single Phase System)
Water at normal pressure and at room temperature exists as a single liquid phase, i.e. all the properties of water are uniform throughout this liquid phase. If a small amount of sugar is added to this sample of water, the sugar dissolves but a sample remains as a single liquid phase. However, the properties and composition of this new liquid phase, now the sugar solution, are different from those of pure water. As this solution of sugar in water is containing two substances (binary solution), so it is a mixture and since its properties are uniform, it is homogeneous in character.
(ii) Heterogeneous Phase System (Two Phase System)
Similarly a mixture of ice and water is a two phase system. It may also be defined a separate part of heterogeneous body or system. Q. Define solution. Differentiate between solvent and solute. Ans. Solution:
A one phase homogeneous mixture of two or more kinds of different molecular or ionic substance is called a solution.
The component of the solution which is present in large quantity is called solvent.
The component in small quantity is called a solute.
In a sugar solution water is solvent and sugar is solute.