This set of Ceramics Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Secondary Bonding in Ceramics”.
1. Secondary bonds are much weaker than primary bonds.
a) True
b) False
View Answer
Explanation: Secondary bonds are obtained by formation of temporary or permanent dipoles. These dipolar interactions are very weak and tend to break by small force. However, covalent, ionic and metallic bonds are much stronger. Therefore, secondary bonds are much weaker than primary bonds.
2. Van der Waals bonding is also known as _________
a) hydrogen bonding
b) dipole-dipole interactions
c) London dispersion forces
d) polar moments
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Explanation: Van der Waals forces were discovered by German-American physicist Fritz London. The name ’London dispersion forces’ is given on honor of his notable work.
3. Which type of bonding is observed between layers of carbon atoms in graphite?
a) Hydrogen bonding
b) Covalent bonding
c) Dipole-dipole interactions
d) Van der Waals forces
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Explanation: In graphite, carbon atoms are bonded together by covalent bonds. However, the adjacent layers of carbon atoms are loosely bonded with each other by Van der Waals forces. These forces allow slight movement between the layers. This property makes it useful as lubricants.
4. What is the reason behind slip propagation between the layers of pyrophillite?
a) Cancellation of charges
b) Dislocations
c) Twinning
d) Van der Waals forces
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Explanation: Pyrophillite consists of layers of silicate. The adjacent oxygen ions of the layers are bonded by Van der Waals forces. Due to weak bonding, slip propagation in direction parallel to adjacent layers is possible.
5. Which of the following ceramics show Van der Waals forces?
a) Molybdenum disulphide
b) Barium oxide
c) Manganese sulphide
d) Magnesium dioxide
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Explanation: Molybdenum disulphide has MoS₆ units, where molybdenum is surrounded by six sulphur atoms. The layers are connected to each other by Van der Waals forces so there is slip between sulphur atoms.
6. Which of the following statement is correct?
a) Hydrogen bonds are weaker than van der Waals bonds
b) Hydrogen bonds are stronger than van der Waals bonds
c) Hydrogen bonds are stronger than covalent bonds
d) Hydrogen bonds are stronger than ionic bonds
View Answer
Explanation: Hydrogen bonds occur when hydrogen atom form bond with more electronegative atoms. This bonding between hydrogen atom having covalent bond and a more electronegative atom is considerably stronger than van der Waals forces but not as strong as primary bonds.
7. Which of the following is an example of hydrogen bonding in ceramics?
a) Kaolinite
b) Silica
c) Fluorspar
d) Cinnabar
View Answer
Explanation: Kaolinite is an example of hydrogen bonding. Hydrogen bonds can be formed between basal oxygen atoms in one plane and hydroxyl groups in another plane. Silica, fluorspar and cinnabar are other examples of ceramics not having hydrogen bonding.
8. Why is kaolinite easy for molding?
a) Grain boundary movement
b) Frank reed source
c) Slip between layers
d) Van der Waals forces
View Answer
Explanation: Kaolinite has hydrogen bonding. As the atoms or molecules are loosely bonded to each other, they can easily slide over the adjacent layers. Thus, they are good for molding purposes.
9. Iodine chloride is a solid but bromine is liquid at 0°C. Why?
a) Hydrogen bonding
b) Columbic force
c) Van der Waals forces
d) Dipole-dipole interactions
View Answer
Explanation: The intermolecular dipole-dipole interactions between iodine chloride molecules are so strong that the molecules can hardly move. Due to this, iodine chloride is a solid at room temperature. However the dipole interactions between bromine molecules are not sufficient to hold all the molecules together. Hence, it is liquid at room temperature.
10. Dipole-dipole interactions occur between __________
a) two dipolar molecules
b) two oppositely charged molecules
c) polar and non-polar molecules
d) cation and anion
View Answer
Explanation: A molecule consists of two charges which makes it a dipole. One dipole having a polar end attracts or repels another dipole depending on their orientation. Thus dipole-dipole interactions occur only between two dipoles or between a dipole and induced dipolar molecules.
Sanfoundry Global Education & Learning Series – Ceramics Engineering.
To practice all areas of Ceramics Engineering, here is complete set of Multiple Choice Questions and Answers.
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