This set of Engineering Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Colloids – 2”.
1. What is the colloidal mixture of solid with solid called?
a) Solid sol
b) Liquid sol
Explanation: 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?
Explanation: 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?
d) Solid sol
Explanation: 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?
Explanation: 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
Explanation: 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.
c) Salt water
d) Sugar solution
Explanation: 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.
d) Rice milk
Explanation: 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.
Explanation: 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.
c) Froths of air
Explanation: 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.
c) Pumice stone
Explanation: 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.
Sanfoundry Global Education & Learning Series – Engineering Chemistry.
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