Engineering Chemistry Multiple Choice Questions on “Colloids – 2”.
1. What is the colloidal mixture of solid with solid called?
a) Solid sol
b) Liquid sol
c) Sol
d) Gel
Answer: a
Clarification: Since in this colloidal mixture, a solid is mixed with another solid, the molecules are having a tight bond between them. Hence it is called solid sol.
2. What is the colloidal solution of liquid with solid called?
a) Sol
b) Gel
c) Foam
d) Form
Answer: a
Clarification: In the colloidal mixture of solid and liquid which is called sol, the bond is not as strong as compared to solid sol. The bond is lightly less bonded. Hence the name sol.
3. What is a colloidal solution of liquid in liquid called?
a) Foam
b) Form
c) Emulsification
d) Solid sol
Answer: c
Clarification: Since we know that the molecular bond between the liquid and liquid is not that much strong and hence will sometimes form stable solutions (may be homo or heterogeneous).
4. What is the colloidal solution of liquid and gas called?
a) Aerosol
b) Gel
c) Sol
d) Emulsion
Answer: a
Clarification: We know that out of all other bonds, the weakest bond is between a gaseous molecule and a gaseous molecule. The next weakest bond after this is between a liquid and a gaseous molecule. Such a colloid is called an aerosol.
5. Which of the following colloidal combinations is not possible?
a) Liquid in solid
b) Solid in liquid
c) Gas in gas
d) Gas in solid
Answer: c
Clarification: We know that gases are completely miscible in nature. Hence n number of gases together will be considered only as a single molecule. Hence such a colloidal combination is not possible.
6. Identify the liquid-liquid emulsion from the following.
a) Milk
b) Oil
c) Salt water
d) Sugar solution
Answer: a
Clarification: We know that milk is a combination of many materials like vitamins, minerals, fats etc and hence forms a colloidal solution. Since these materials are so microscopic and are dispersed in a liquid, milk is an example of an emulsion.
7. Identify a sol from the following.
a) Stone
b) Paint
c) Ink
d) Rice milk
Answer: b
Clarification: Paint is thicker as compared to other liquid fluids. It’s hardness scale is assumed to be 9 on the Mohr’s scale which is next to kerosene. Hence paint is considered to a solid liquid sol.
8. Identify a gel from the following.
a) Curd
b) Cheese
c) Yogurt
d) Yolk
Answer: a
Clarification: Curd is got after processing from milk. It is considered to have a stronger bond than cheese and weaker bond than milk. Hence it is considered to be a liquid solid gel.
9. Identify the foam from the following.
a) Bubbles
b) Cake
c) Froths of air
d) Soap
Answer: c
Clarification: We know that froths of air are similar to bubbles but they have more moisture content in them as compared to bubbles. The composition of froths is nothing but a mixture of water and moisture. Hence it is gas-liquid foam.
10. Identify the form from the following.
a) Cheese
b) Paint
c) Pumice stone
d) Cork
Answer: c
Clarification: According to the hardness scale, it is found that pumice stone is stronger than lime stone but is weaker than quartz. Hence it is a colloid of solid and a gas (moisture). So, it is a form.