Unit Solutions are homogeneous mixtures of two or more than two components. By homogenous mixture we mean that its composition and properties are uniform throughout the mixture. Generally, the component that is present in the largest quantity is known as solvent . Solvent determines the physical state in which solution exists.
One or more components present in the solution other than solvent are called solutes. In this Unit we shall consider only binary solutions (i.e., Type of Solution Solute Solvent Common Examples Gaseous Solutions Gas Gas Mixture of oxygen and nitrogen gases Gas Chloroform mixed with nitrogen gas Solid Gas Camphor in nitrogen gas Liquid Solutions Gas Oxygen dissolved in water Ethanol dissolved in water Solid Glucose dissolved in water Solid Solutions Gas Solid Solution of hydrogen in palladium Solid Amalgam of mercury with sodium Solid Solid Copper dissolved in gold Table . : Types of Solutions consisting of two components). Here each component may be solid, liquid or in gaseous state and are summarised in Table .
. Composition of a solution can be described by expressing its concentration. The latter can be expressed either qualitatively or quantitatively. For example, qualitatively we can say that the solution is dilute (i.e., relatively very small quantity of solute) or it is concentrated (i.e., relatively very large quantity of solute).
But in real life these kinds of description can add to lot of confusion and thus the need for a quantitative description of the solution. There are several ways by which we can describe the concentration of the solution quantitatively. (i) Mass percentage ( w / w ) : The mass percentage of a component of a solution is defined as: Mass % of a component Mass of the component in the solution Total mass of the solution ( . ) For example, if a solution is described by % glucose in water by mass, it means that g of glucose is dissolved in g of water resulting in a g solution.
Concentration described by mass percentage is commonly used in industrial chemical applications. For example, commercial bleaching solution contains . mass percentage of sodium hypochlorite in water. (ii) Volume percentage (V/V) : The volume percentage is defined as: Volume % of a component = Volume of the component Total volume of solution ( .