Scribd
Upload
2K views11 pages

Department of Chemistry: Determination of Critical Solution Temperature of Phenol-Water System

This document outlines an experiment to determine the critical solution temperature of a phenol-water system. The objectives, requirements, theory, procedure, observations, calculations, results, and precautions are described. The key steps are to mix varying ratios of phenol and water, heat each mixture while stirring until fully miscible, cool and note the temperature where turbidity reappears, and determine the maximum temperature where miscibility occurs across all ratios, which is the critical solution temperature. The experiment aims to find the temperature at which phenol and water become completely miscible in all proportions.

Uploaded by

zh2607903
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
2K views11 pages

Department of Chemistry: Determination of Critical Solution Temperature of Phenol-Water System

This document outlines an experiment to determine the critical solution temperature of a phenol-water system. The objectives, requirements, theory, procedure, observations, calculations, results, and precautions are described. The key steps are to mix varying ratios of phenol and water, heat each mixture while stirring until fully miscible, cool and note the temperature where turbidity reappears, and determine the maximum temperature where miscibility occurs across all ratios, which is the critical solution temperature. The experiment aims to find the temperature at which phenol and water become completely miscible in all proportions.

Uploaded by

zh2607903
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 11

Department of chemistry

Determination of critical solution


temperature of phenol-water system

Supervised by:-
Prof.Anindya Dutta
Dr. Rajarshi Chakrabarti
Objective :- determination of critical solution
temperature of phenol- water system.
• Requirements:-
• a) glasswares :-
1) weighing bottle and dropper
2) Two glass test tubes one with wide
bore
3)Glass stirrer
4)Beaker
b) chemicals:-1)Phenol
2)distilled water
theory :- Two liquids when mixed may be(i)completely miscible,
(ii) completely immiscible,(iii)partially miscibe . In case (iii) one will
have a definite solubility in other . Example of such cases are phenol-
water system.if we add phenol to water it will be soluble up to a
certain limit and this solubility value will increase with increase in
temperature.similarly,if we add water to phenol same phenomena will
be observed . The number of homogeneous, mechanically separable
and physically distinct parts of a heterogeneous system is known as
the number of phases, P, of the system. each phase is separated from
other phases by a physical boundary. When an equilibrium exists
between a number of phases under external controlling conditions
such as temperature, pressure, and concentration, the following
relationship holds good :
F = C-P + 2 ………. 1
where P = number of Phases in equilibrium,
C = number of Components in the system, and
F = number of degrees of Freedom.
Equation (1) is called the Phase Rule, which relates the phases,
components and degrees of freedom of the system.
When 2 partially miscible liquids are mixed and shaken
together, we get 2 solutions of different compositions.
e.g. on shaking phenol and water, we get 2 layers : the
upper layer is a solution of water in phenol,and the
lower layer is a solution of phenol in water. At a fixed
temp, the composition of each solution is fixed, and
both the solutions are in equilibrium.
Above a particular temperature, such solutions are
completely miscible in all proportions. Such a
temperature is known as the Critical Solution
Temperature (CST) or Consolute Temperature.
Diag. experimental arrangement for cst determination of
phenol water system
• Procedure:- CST for Phenol - Water system
1) Weigh out about 5.0 g of phenol in a dry boiling tube.
2) Add 2.0 ml of distilled water. The solution is stirred.
3) Heat the solution in a water bath, with continuous stirring.
• 4)At a certain temperature, the mixture becomes clear. Note this
temperature (t1˚C).
5) Remove the tube from the water bath, and allow the solution to
cool down slowly. Note the temperature at which the turbidity
‘ re-appears (t2˚C).
6) Repeat Steps 2 to 6, after each addition of 2 ml of solution,
followed by heating and subsequent cooling, note the temperature of
disappearance of turbidity, and the temperature of the re-
appearance of turbidity.
• The observation is that the temperature (oC) of complete
miscibility rises, reaches a maximum value,and then decreases.
Observation and calculation:-
La . Te p= ….˚
(
% of phenol= (density × volume)of phenol )×100/((density × volume)of
phenol + volume of water)
Weight of phe ol=……g
De sity of phe ol =……g/ l
De sity of water =……g/ l
S.N Volume of wt % of miscibility Temp.() Average
water (ml) phenol Turbidity Turbidity miscibility
in water Disappear appear temp

1.
2.
3.
Fig. soubility curve of phenol water-system
Calculation:- 1) A curve is plotted between
miscibility temp. and conc. Of phenol.
2) The maximum of the solubility curve gives the
value of critical solution temp.

Result :- the critical solution temperature of


phe ol water syste = …..˚
A d % of phe ol at CST is = …..%
Precautions :- 1) temp. of solution should be
increased very slowly.
2)Mixture should be continuously and uniformly
stirred.
3)Care should be taken while handling phenol.

The end
Thank you

You might also like