Question

Do some research on one application of colligative properties or colloids that you find particularly interesting. Present a summary in your own words(150 words or more). Make sure your posting contains the following: How did you learn about this application? Why did you choose it? What did you learn from your research? Sources (books, articles, websites) you collected information from. ( I will only accept typed responses)

Answer 1

Colligative properties

Colligative properties which only depend on the number of solute particles present in a given amount of solvent, and not in any way upon the nature of the solute particle.

* lowering of vapor pressure

* elevation of boiling point

* depression of freezing point

* osmotic pressure

Osmotic pressure

The osmotic pressure of a solution at a given temperature is the minimum excess pressure that must be applied to the solution in order to prevent the entry of solvent into it through a perfectly semi permeable membrane separating the solvent and the solution. When a pressure greater than its osmotic pressure is applied on a solution kept separated from the pure solvent by means of a semi permeable membrane, there occurs a flow of solvent through the membrane. The phenomenon is called reverse osmosis. Reverse osmosis technique is used for the n desalination of water ( purification of sea water and brackish water). The process of removing saline impurities from sea water is called desalination. In many countries like Middle East countries where fresh water is not abundant, desalination of sea water or brackish water is carried out to get drinkable water. In this process saline water is kept separated from a pure sample of water by means of strong semipermeable Membrane. A pressure just higher than its osmotic pressure applied on the sample of saline water. Water then flows out of the saline water into the pure sample through semipermeable membrane. In this process of desalination, the water is forced out of the saline water, not the salt. Very high pressure of order thousand of kpa have to applied in this method. Fresh water thus obtained is suitable for drinking purposes.