TH -203 EBULLIOMETRIC DETERMINATION OF THE `INFINITE DILUTION - - PowerPoint PPT Presentation

TH -203

EBULLIOMETRIC DETERMINATION OF THE `INFINITE DILUTION ACTIVITY COEFFICIENT' (IDAC)

Instructor :

• Prof. H S Shankar

Staff : A Francis TAs : Harini M Prawal Agarwal Shubham Gupta

AIM

• To determine "Infinite Dilution Activity Coefficient" (IDAC) of

a binary mixture at atmospheric pressure using differential ebulliometry and the limiting slope method.

• To estimate the parameters in the activity coefficients
• To estimate the parameters in the activity coefficients

correlations such as Van Laar/Wilson.

Infinite Dilution Activity Coefficient (IDAC)

At infinite dilution the deviation from ideality occurs. Phase equilibrium calculation can be performed

using IDAC. using IDAC.

Parameters of activity coefficient model can be

determined.

Theory of IDAC

Assuming Ideal Vapour Phase and Negligible Poynting correction Differentiating with respect to x1 and applying the conditions of infinite dilution we get,

1 1 1 2 2 2

P x p x p γ γ = +

2 2 1 p

dP dT P dT dx γ

∝ ∝

• −
• =

By Antonie equation The quantity is calculated experimentally by plotting T vs x1

1 P

dTdx

∝

• (

)

2 2 2

dP P B dT T C = +

1 1 p

P γ ∝

• =

Ebulliometer

• It is a device which is used for precise

and simultaneous measurement of both, the bubble point of a liquid and the dew point of the vapor A) reflux condenser A) reflux condenser B) dropper C) thermometer socket D) bulb E) heating compartment with heating coil F) draining valve

Procedure

• Prepare 1%,3% and 5% (mole %)

solutions of binary mixtures

• Pour them in 3 different ebulliometers
• Set pressure of each ebulliometer to 1 atm
• Switch on heating supply.
• When the steady state temperature is attained,

measure average drop rate (per min) of condensed vapor

• Record both temperature and the drop rate.

Procedure

• Alter the rheostat by one division and

record the temperature and drop rate.

• Get 4 set of readings with drop rate <

100/min

• Plot Temperature vs drop rate for each

solution.

• Find bubble point temperature (at 0 drop rate)

by extrapolation.

• Fit a straight line through a plot of bubble point

temperature vs concentration (x1) and find the slope (dT/dx1).

• Calculate the IDAC

procedure

Repeat the above steps for other dilute (complementary

experiment carried by other group).

Check for positive or negative deviation from Raoults law.

Determine Van Laar or Wilson’s parameters and compare with

Determine Van Laar or Wilson’s parameters and compare with

literature data, if available.

EXPERIMENTAL DATA 1 mole% binary mixture 3 mole % binary mixture 5 mole % binary mixture Temp. Drop rate/ min Temp. Drop rate/ min Temp. Drop rate/ min

Data analysis and reporting

min min min RUN1

• RUN2
• RUN3
• RUN4

Data analysis

emperature bble point perature

• For 3 different concentrations

Temp Drop rate Mole fraction Bubble Temper

• Calculate the activity coefficients