SUSPENSION

SUSPENSION

A heterogeneous mixture of insoluble particles of solute, spread throughout a solvent, is called a suspension. The particle size (diameter) in a suspension is more than 10-5 cm. The particles has a tendency to settle down at the bottom of the vessel and can be filtered out, because their size is bigger than the size of the pores of the filter paper.

Examples:

•   Milk of magnesia is a suspension of magnesium hydroxide, Mg(OH)₂, in water. 
• Lime water (used for white wash) is a suspension of calcium hydroxide in water. 
• Paints are suspensions of coloured substances in water or some other liquid. 
• Bleaching powder in water is also a suspension since bleaching powder is insoluble in water. 
• The particles of suspension are visible to the naked eye.

PROPERTIES OF SUSPENSION:

• A suspension is a heterogeneous mixture.
• The solid particles of a suspension are so large in size (more than 10-5 cm or 10-7 m or 100 nm) that they are visible to the naked eye.
• The particles of a suspension scatter a beam of light passing through it and makes its path visible (show tyndall effect).
• The solid particles of a suspension settle down when it is allowed to stand for sometime. In other words, a suspension is unstable.
• The particles of a suspension cannot pass through a filter paper. Thus, when a suspension is filtered, the solid particles remain as a residue on the filter paper.
• Suspensions are either opaque or translucent.