Engineering Chemistry S Datta

COLLOIDS 291
3. Which one is the most efficient in coagulating a ferric hydroxide sol?
(a) K 4
[Fe(CN) 6
] (b) K 3
[Fe (CN) 6
]
(c) KCl.
4. Which process is used for the purification of a colloidal solution?
(a) Dialysis
(c) Dissolution.
(b) Peptization
5. The random zig-zag movement of colloidal particles in a dispersion medium is called
(a) Tyndall effect
(b) Brownian movement
(c) Dialysis.
6. Which is a protective colloid?
(a) K 4
[Fe(CN) 6
]
(b) NaCl
(c) Gelatin.
7. Haemoglobin in blood is
(a) Hydrophobic colloid
(b) Hydrophilic colloid
(c) Gel.
8. Colloidal particles are electrically charged. This can be demonstrated by
(a) Peptization
(b) Electrophoresis
(c) Dialysis.
9. Smoke is a colloidal sol of
(a) Solid dispersed in gas
(b) Gas dispersed in solid
(c) Liquid dispersed in gas.
10. Milk is an emulsion of
(a) Casein dispersed in water.
(b) Lactose dispersed in water.
(c) Fat globules dispersed in water.
11. Bancroft rule states that
(a) Colloidal particles are always charged
(b) Light falling in the medium is scattered by the colloidal particles.
(c) The phase in which the emulsifier is more soluble is the outer phase.
12. Soaps and detergents act as
(a) Stabilizers
(b) Emulsifiers
(c) Coagulating agents.