Oswaal CBSE CCE Laboratory Manual For Class 9 (Term 1) science
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IS MATTER AROUND US PURE Aim To Prepare a a true solution of common salt, sugar and alum. b a suspension of soil, chalk powder and fine sand in water. c a colloidal solution of starch in water and egg albumin milk in water and distinguish between these on the basis of i transparency ii filtration criterion iii stability.
Materials Required Beaker 250 ml , glass rod, measuring cylinder, common salt, water, starch powder and black board chalk.
THEORY A true solution is a homogeneous mixture of two or more substances. The solute and solvent particles cannot be observed by the naked eye as they are very small. A suspension is a heterogeneous mixture of two or more substances. The solute particles of suspension are often visible by the naked eyes. A colloidal is a microscopically small substance. That is equally dispersed throughout another material.
To differenciate between the true solution, suspension and colloidal on the basis of transparency Take three test- tubes and label them A, B and C. A filled with true solution of common salt, B filled with suspension of chalk powder, and C filled with colloidal solution of egg albumin. After this we will observe all three test- tubes carefully. i In test- tube A true solution , the light passes through the solution. ii In test- tube B suspension , light does not passes though the solution. iii In test- tube C colloidal , the beam of light gets scattered.
Oswaal CBSE CCE Laboratory Manual For Class 9 Term 1 science
Publisher Oswaal Books