Pulp and Paper Multiple Choice Questions on “Colloidal Chemistry”.
1. A colloid is a stable combination of particles of one substance that are dissolved or suspended in a second substance
a) True
b) False
Answer: a
Clarification: The particles have at least one of the principal dimensions (somewhat arbitrarily) from about 1 nm to 1 µm. Colloids include gels, sols, and emulsions.
2. The dispersion medium for the formation of colloids forms a non-continuous phase.
a) True
b) False
Answer: b
Clarification: A colloid may be considered to include the gas, liquid, or solid in which the particles are dispersed in addition to the particles themselves. The dispersion medium forms a continuous phase.
3. An _________ is a sol with the continuous phase a gas. Fog is an _________ of water droplets.
a) Aerosol
b) Emulsion
c) Agglomerate
d) Electrophoresis
Answer: a
Clarification: It’s a colloid of fine solid particles or liquid droplets, in air or another gas. These could be natural or artificial. Fog is an aerosol of water droplets; smoke is an aerosol of solid particles.
4. An _________ is a sol in which the suspended particles are liquid droplets and the continuous phase is also a liquid. The 2 phases are immiscible, otherwise a solution would form.
a) Aerosol
b) Emulsion
c) Agglomerate
d) Electrophoresis
Answer: b
Clarification: It’s a mixture of 2 or more liquids that are normally immiscible. These are the parts of a more general class of two-phase systems of matter named as colloids.
5. A _________ is a sol of solid particles scattered in a liquid. Foam is a colloidal system in which gas bubbles dispersed in a liquid or solid.
a) Colloidal suspension
b) Streaming potential
c) Sedimentation potential
d) Electrophoresis
Answer: a
Clarification: A mixture in which mini particles of a substance are dispersed throughout the whole gas or liquid. If a suspension’s left undisturbed, the particles are possible to settle to the bottom.
6. The _________ of colloids are of maximum importance since the interaction of the particles with each other and the principal phase is of primary concern.
a) Magnitude
b) Shape
c) Surface
d) Size
Answer: c
Clarification: The surface—to—volume ratio of a given particle shape is inversely proportional to the length of the principal axis. The surfaces of colloids are of maximum importance since the interaction of the particles with each other and the principal phase is of primary concern.
7. As the concentration increases to the critical micelle concentration(C.M.C.) soap particles abruptly collected into spherical structures called _________
a) Ball
b) Sphere of ions
c) Micelles
d) Dirt particle
Answer: c
Clarification: Micelles are groups of about 20 to several hundred molecules with the non-polar (hydrophobic) hydrocarbon tail toward the centre and the polar (hydrophilic) head toward the surface in contact with water.
8. _________ is the movement of charged surfaces with corresponding ions and H2O in the stationary liquid induced by an external field.
a) Colloidal suspension
b) Emulsion
c) Sedimentation potential
d) Electrophoresis
Answer: d
Explanation It’s a technique utilized in laboratories in order to separate macro molecules based on size. The technique applies a (–ve) charge so proteins move towards a (+ve).
9. _________ is the charged field generated by charged particles moving in a stationary liquid.
a) Colloidal suspension
b) Emulsion
c) Sedimentation potential
d) Electrophoresis
Answer: c
Clarification: It happens when scattered particles move under the affects of either gravity or centrifugation in a medium. This motion distorts the stable equilibrium symmetry of the particle’s double layer.
10. _________ is the generation of an electric field by locomotion of the liquid along stationary charged surfaces.
a) Colloidal suspension
b) Streaming potential
c) Sedimentation potential
d) Electrophoresis
Answer: b
Clarification: A streaming current and streaming potential are 2 interrelated electro-kinetic phenomena studied in the areas of surface chemistry and electrochemistry. They are the potential which originates when an electrolyte is driven by a pressure gradient through a channel or porous plug with the charged walls.
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