osmotic pressure. Application of Reverse osmosis in water purification : Figure . Osmosis & Reverse osmosis Reverse osmosis is used in the desalination of sea water and also in the purification of drinking water. A simple set up used in both the process is shown in the figure .
. When a pressure higher than the osmotic pressure is applied on the solution side (sea water) the water molecules moves from solution side to the solvent side through semipermeable membrane (Opposite to the Osmotic flow). Pure water can be collected. There are different types of semipermeable membranes used in this process.
The membrane used for reverse osmosis has to withstand high pressures. Generally, cellulose acetate or polyamide membranes are commonly used in commercial systems. The selection of membrane used for reverse osmosis will be decided based on the nature of the input water. Example Problem- : At 400K .
g of an unknown substance is dissolved in a solvent and the solution is made to . L. Its osmotic pressure is found to be . bar.
Calculate the molar mass of the unknown substance. Molar mass mass of unknown solute × RT osmotic pressure × volume of solution . × . × - × .
× . . gram mol - ? ) What is the mass of glucose (C H O ) in one litre solution which is isotonic with g L - of urea (NH CO NH ) ?
Evaluate Yourself Unit Unit - - - - . Abnormal molar mass The molar masses of the nonvolatile solutes can be calculated accurately using the experimentally determined colligative properties. In this method, we assume that the solution is very dilute and there is no dissociation or association of solute particles in the solution. In a concentrated solution, the interaction between the solute and solvent becomes significant and reflected in the measured colligative properties.
Similarly, the dissociation or association of solute molecules would alter the total number of particles present in the solution and hence affect the