91. During adsorption
A
$$T\Delta S$$ is positive
B
$$\Delta H - T\Delta S$$ is negative
C
$$\Delta H$$ is positive
D
$$T\Delta S$$ and $$\Delta G$$ become zero
Answer :
$$\Delta H - T\Delta S$$ is negative
92. Associated colloids :
A
raise both the surface tension and viscosity of water
B
lower both the surface tension and viscosity of water
C
lower the surface tension and raise the viscosity of water
D
have greater concentration at the surface layer than the bulk of the solution
Answer :
lower the surface tension and raise the viscosity of water
93. The size of particles in suspension, true solution and colloidal solution varies in the order :
A
suspension > colloidal > true solution
B
true solution > suspension > colloidal
C
suspension > colloidal = true solution
D
none of these
Answer :
suspension > colloidal > true solution
94. Although, nitrogen does not adsorb on a surface at room temperature, it adsorbs on the surface at $$83\,K.$$ Which one of the following statements is correct ?
A
At $$83\,K,$$ there is formation of monolayer
B
At $$83\,K,$$ nitrogen is adsorbed as atoms
C
At $$83\,K,$$ nitrogen molecules are held by chemical bonds
D
At $$83\,K,$$ there is formation of multimolecular layers
Answer :
At $$83\,K,$$ there is formation of multimolecular layers
95. Smoke is an example of :
A
Solid dispersed in solid
B
Gas dispersed in liquid
C
Solid dispersed in gas
D
Gas dispersed in solid
Answer :
Solid dispersed in gas
96. Chemisorption involves formation of bond between gaseous molecules or atoms and the solid surface for which high energy is required. Thus it is also referred as
A
chemical adsorption
B
positive adsorption
C
activated adsorption
D
passive adsorption
Answer :
activated adsorption
97.
Which of the following statements are correct?
(i) On the application of an electric field, the particles of lyophobic sol may move in both direction or not move at all.
(ii) Surface tension of lyophobic sols is similar to that of the dispersion medium.
(iii) Electro-osmosis is the movement of the particles of dispersion medium under the influence of an electric field.
A
(i), (ii) and (iii)
B
(i) and (iii)
C
(ii) and (iii)
D
(i) and (ii)
Answer :
(ii) and (iii)
98. Which of the following constitutes irreversible colloidal system in water as dispersion medium?
A
Clay
B
Platinum
C
$$Fe{\left( {OH} \right)_3}$$
D
All of these
Answer :
All of these
99. Point out the false statement
A
Brownian movement and Tyndall effect are shown by colloidal systems.
B
Gold number is a measure of the protective power of a lyophillic colloid
C
The colloidal solution of a liquid in liquid is called gel
D
Hardy - Schulze rule is related with coagulation.
Answer :
The colloidal solution of a liquid in liquid is called gel
100.
Which of the following phenomenon is applicable to the process shown in the figure?
A
Absorption
B
Adsorption
C
Coagulation
D
Emulsification
Answer :
Adsorption