| Aim: | Preparation of True solution of common salt, sugar and alum, A suspension of soil, chalk powder and fine sand in water, A colloidal solution of starch in water and egg albumin/ milk in water and distinguish between these on the basis of: transparency, filtration criterion, stability |
| Theory: | A true solution is a type of solution where the solute particles have a diameter of less than 1 nm (10-9 metres) and cannot be seen with the naked eye. These particles do not scatter light, do not separate out through filtration, and do not settle down. The solution is homogeneous, meaning that the solute particles are evenly distributed throughout the solvent at a molecular level. |
| Properties of True Solutions: | ⚫ A true solution is a homogeneous mixture of solute and solvent, where the solute particles are smaller than 1 nm (10-9m) in size, making them invisible to the naked eye. ⚫ These particles do not scatter light and do not display the Tyndall effect. ⚫ The solute particles cannot be separated by filtration and the solution remains uniform and stable. Additionally, the solution is clear and transparent.  |
| Materials Required: | Sugar, Beakers, Common salt (Sodium chloride), Alum, Test tubes, Glass Rod, Water. |
| Procedure: | ⚫ Take three beakers and pour 100 mL of water into each. Label them as A, B, and C, respectively. ⚫ Add 10g of finely powdered common salt, sugar, and alum separately into each beaker. ⚫ Stir the mixture in each beaker using a glass rod. ⚫ Transfer the resulting solutions into test tubes and label them as A, B, and C, respectively |
Observation Table
| Property | Experimental Procedure | Observation | Inference |
| Transparency | Each test tube has a small strip of cellophane paper glued on it, and the coloured paper of each test tube can be seen from the other side. | Colour spot is evidently seen on test tubes when seen from the other side. | Colour spot is evidently seen on test tubes when seen from the other side. |
| Filtration Criterion | Filtrate the contents of test tubes labelled A, B, and C. | Colour spot is evidently seen on test tubes when seen from the other side. | Colour spot is evidently seen on test tubes when seen from the other side. |
| Stability | Allow 20-25 minutes for the test tubes to rest without being disturbed. | Colour spot is evidently seen on test tubes when seen from the other side. | Colour spot is evidently seen on test tubes when seen from the other side. |
| Results and Discussion: | True solutions are clear and transparent. They pass through the filter paper without leaving any trace. The filtrate is translucent as well. |
| Precautions: | ⚫ Handle the materials and solutions with care. ⚫ While filtering a solution drop the contents along a glass rod into the funnel. ⚫ Keep the sample undisturbed while checking stability. |