SOLUTIONS OF LIQUIDS IN LIQUIDS

types

1. completely disciple liquids(form a true solution)

2. partially miscible liquids(form a conjugated solution)

3. liquids practically immiscible

completely miscible liquids definition

liquids which mix up into each other in all proportions form completely miscible solutions.

examples of completely miscible liquids

1. water and alcohol

2. alcohol and ether

properties of completely miscible liquids

are not generally additive

1. volume of solution is not equal to the sum of volume of solute and solvent. volume may decrease but in some cases it increases

2. heat may evolve or absorb during the formation of each solution

3. components of such solution cam usually be separated by fractional distillation

partially miscible liquids

the liquids which dissolve into each other upto limited extent are called partially miscible liquids and they form partially miscible(conjugate)solutions.

examples of partially miscible liquids

on shaking equal volumes of ether water, ether dissolves water to the extent of 1.2 percent and water dissolves ether upto the extent of 6.5 percent

conjugate solutions

two partially miscible liquids form separate layers which are solutions of each other are called as conjugated solutions

examples of partially miscible liquids

phenol water system

triethylamine water system

nicotine water system

phenol water system

if we mix equal volumes of water and phenol, they are partially miscible and form two seperate layers.

upper layer:

upper layer is the solution of phenol in water.

at 25 degree, upper solution is 5 percent solution of phenol in water

phenol is a solute in upper layer

lower layer:

lower layer is the solution of water in phenol

at 25 degree, lower layer is 30 percent solution of water in phenol

water acts as a solute in lower layer

increase in temperature:

when the temperature of water phenol system is increased, the compositions of both the layers change. with increasing temp, solubility of phenol and water increases in each other. water stats moving from upper to lower layer and phenol travels from lower to upper layer

when temperature of this system approaches 69.5 degree, a homogeneous mixture of the two components is obtained. this homogeneous mixture contains 34 percent phenol and 66 percent water

critical solution temp/ upper consulate temp

the temperature at which two conjugate solutions merge into one another to form a true solution is called critical solution or upper consulate temp

examples of critical solution temp

upper consulate temp for water aniline system is 167 degree. at this temp, we get one layer with 15 percent water

methanol cyclohexane system has upper consulate temperature 49.1 degree with 29 percent methanol

upper consulate temp for phenol water system is 65.9 degree