Master of Science II (Physical Chemistry)
Examination: Oct Nov 2016 Semester IV (New CGPA)
SLR No. Day
Date Time Subject Name Paper No. Seat No.
SLR SD
250
Thursday
24/11/2016
02:30 P.M
to
05:00 P.M
Surface Chemistry
C
XVI
Instructions: Attempt in all five questions.
Section I is compulsory.
Attempt any two questions from Section II and any two from
Section III.
Answer to all questions (Section II and III) should be written
in the one answer book.
All questions carry equal marks.
Figures to the right indicate full marks.
Total Marks:70
SECTION I
Q.1 Solve the following: 14
What is capillary constant?
Does the ratio of surface area to volume affects the shape of the particles in
sintering? Indicate yes or no.
"Positive adsorption is the phenomenon in which surface tension of liquid
decreases with concentration of surfactant", state whether statement is true or
false.
What is negative catalysis?
In homogeneous catalysis
The catalyst and the reactants should be gases.
ii) The catalyst and reactants are all solids.
iii) The catalyst and the reactants should form single phase.
iv) The catalyst and reactants are all liquids.
Define specific surface free energy of solids.
"If volume ratio of water to oil is three or more an oil/water emulsion is more
probable than water/oil emulsion", state whether this statement is true or
false.
Point out the effect of temperature on detergent efficiency.
The surface tension of water and carbon disulphide are 72.8 x 10-3 N/m and
32.3 x 10-3 N/m. Predict whether carbon disulphide spreads on the surface of
water.
"Mercury on flat solid surface takes spherical shape", why?
What is expanding pressure?
The nanoparticles are dimensional.
Zero one two three
What is contact angle hysteresis?
A square frame of side 1 is dipped in a liquid soap when it is taken out of the
liquid, a film is formed on it. If surface tension is γ then force acting on it is
2γ 1 8γ 1 4γ 1 16γ 1
Page 1 of 2
SECTION II
Q.2 Discuss in brief the theory and energetic of micellization.
For sodium dedocyl sulphate the free energy of micellization is -5.3 kcal
mole-1 at 25º C. The calorimetric heat of micellization is 0.5 kcal mole-1.
Calculate entropy change of micellization.
07
Explain the term contact angle and its relation with the wetting of solid
surface by the given liquid. Describe capillary rise method of determination of
contact angle made by the liquid with the solid surface.
07
Q.3 Derive Gibb's adsorption equation with usual notations. Discuss positive and
negative adsorption.
07
Deduce two dimensional ideal equation to describe physical states of
monomolecular films of surfactant on liquid surfaces.
At 20ºC and a surface pressure of 0.10 dynes per cm, lauric acid occupies an
area of 3100 A2 per molecule on a water surface. Assuming the film to be a
two dimensional ideal gas, calculate the gas constant in ergs per degree per
mole.
07
Q.4 Derive Langmuir adsorption isotherm and explain its advantages and
disadvantages.
07
What is point B method? Discuss determination surface area of the solid by
using this method.
07
SECTION III
Q.5 "Describe Bartell method of determination of contact angle made by the
liquid with the solid surface.
05
Describe drop weight method of determination of surface tension. 05
State and explain Trube's rule. 04
Q.6 Discuss maximum bubble pressure method of determination surface Tension
of liquids.
05
Derive equation for spreading coefficient for liquid "B" on the surface of
liquid "A" from thermodynamic consideration.
05
Explain the term cohesion and adhesion energy of the liquids in terms of the
surface tension.
04
Q.7 Write a note on any three of the following. 14
Emulsifiers
Selective wetting.
Herkins-Jura Equation.
Wetting agents