11. Which one of the following forms micelles in aqueous solution above certain concentration?
A
Urea
B
Dodecyl trimethyl ammonium chloride
C
Pyridinium chloride
D
Glucose
Answer :
Dodecyl trimethyl ammonium chloride
12. What is the role of adsorption in froth floatation process used especially for concentration of sulphide ores ?
A
Shape selective catalysts.
B
Adsorption of pine oil on sulphide ore particles.
C
Adsorption of pine oil on impurities.
D
Production of heat in the process of exothermic reaction.
Answer :
Adsorption of pine oil on sulphide ore particles.
13. The dispersed phase in colloidal iron (III) hydroxide and colloidal gold is positively and negatively charged respectively. Which of the following statements is not correct?
A
Magnesium chloride solution coagulates gold sol readily than iron (III) hydroxide sol.
B
Sodium sulphate solution causes coagulation in both sols.
C
Mixing of the two sols has no effect.
D
Coagulation in both sols can be brought about by electrophoresis.
Answer :
Mixing of the two sols has no effect.
14. The ability of anion to bring about coagulation of a given colloid depends upon
A
its charge
B
the sign of the charge alone
C
the magnitude of its charge
D
both magnitude and sign of its charge
Answer :
both magnitude and sign of its charge
15. Colloid of which one of the following can be prepared by electrical dispersion method as well as reduction method ?
A
Sulphur
B
Ferric hydroxide
C
Arsenious sulphide
D
Gold
Answer :
Gold
16. Some medicines are more effective in the colloidal form because of
A
the charged colloidal particles present in it
B
the large surface area and easy assimilation
C
precipitation of medicine in the blood
D
the stabilisation of medicine in colloidal form.
Answer :
the large surface area and easy assimilation
17. The migration of dispersion medium under the influence of an electric potential is called :
A
Cataphoresis
B
Electro-osmosis
C
Electrophoresis
D
Sedimentation
Answer :
Electro-osmosis
18. According to the adsorption theory of catalysis, the speed of the reaction increases because
A
adsorption produces heat which increases the speed of the reaction
B
adsorption lowers the activation energy of the reaction
C
the concentration of reactant molecules at the active centres of the catalyst becomes high due to adsorption
D
in the process of adsorption, the activation energy of the molecules becomes large
Answer :
adsorption lowers the activation energy of the reaction
19. At low pressure, the fraction of the surface covered follows
A
zero order kinetics
B
first order kinetics
C
second order kinetics
D
fractional order kinetics
Answer :
first order kinetics
20. Which of the following has minimum flocculation value for positively charged sol?
A
$$C{l^ - }$$
B
$$SO_4^{2 - }$$
C
$$PO_4^{3 - }$$
D
$${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{4 - }}$$
Answer :
$${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{4 - }}$$