5. Separation by Chromatography
Chromatography is a technique of separating two (or more) dissolved solids which are present in a solution in very small quantities.There are many types of chromatography but the simplest form is the paper chromatography.So, we will study only paper chromatography in this class. By using paper chromatography, we can separate two (or more) different substances present in the same solution. This separation is based on the fact that though two (or more) substances are soluble in the same solvent (say, water) but their solubilities may be different. Some may be more soluble than the others. For example,black ink contains a number of dyes dissolved in water. These dyes have different solubilities in water.This fact is used to separate the dyes present in black ink.
It is most easy to perform chromatography experiments with the mixtures of coloured materials like "inks' and other 'dyes' because they separate to give coloured components which can be seen easily as coloured spots on the paper. A special type of paper called "chromatography paper' is used for carrying out separations by chromatography. For ordinary purposes, however, filter paper can also be used for paper chromatography experiments. We will now describe the process of separation of dissolved solids from a solution by paper chromatography by taking the example of black ink. Black ink is a mixture of several coloured substances (or dyes) which can be separated by paper chromatography.
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Matter in Our Surroundings - Notes
1. 11. Metals Usually Have a Silver or Grey Colour
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2. The Case of a Liquid Solute Dissolved in a Liquid Solvent
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8. 7. Non-Metals may be Solid, Liquid or Gases at the Room Temperature.
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10. 3. Non-Metals are Bad Conductors of Heat and Electricity.
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11. 6. Metals are Usually Strong. They Have High Tensile Strength.
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17. Chemical Formula for daily use material
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24. To Study the Properties of a Compound of Iron and Sulphur
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28. 4. Metals are Lustrous (or Shiny), and can be Polished.
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30. To Separate a Mixture of Alcohol and Water
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31. To Study the Properties of a Solution
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35. 7. Metals are Solids at the Room Temperature
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36. To Study the Properties of a Suspension
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39. To Separate the Salt-Water Mixture (or Salt-Solution)
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46. Separation of Mixture Of Two Solids
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48. 6. Non-Metals are Not Strong. They Have Low Tensile Strength.
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