CHAPTER-11
Industrial Inorganic Chemistry
(B)CERAMICS
Text Book Question and Answers
I. Answer the following questions
1. Write one similar character between glass and ceramics
Both glass and ceramics are brittle, heat resistant and non-corrosive to chemicals. Both glass and ceramics can be coloured by metallic oxides.
2. What are the merits of glazing the earthern ware?
The merits of glazing the earthern ware is it makes them non porous.
II. Fill the table with suitable words.
| SL.NO. | Additive | Advantages |
| 1 | Clay | Thermally setting material |
| 2 | Flint | They do not absorb water. Hence they do not get transformed on heating. And do not shrink(controlled the cracking of ceramics) |
| 3 | Quartz | They do not absorb water. Hence they do not get transformed on heating. And do not shrink(controlled the cracking of ceramics) |
| 4 | Feld spar | Gives a smoother glossy finish and gives strength |
III. Fill in the blanks with suitable answer
| SL.NO. | Uses of ceramics | Reason |
| 1 | Floor vitrified tiles | Hard and shining ceramics |
| 2 | Part of electrical gadgetry | Good insulator |
| 3 | Pickle jar | Non-porous |
Additional Questions
1. What is ceramics?
Prepared out of specific mud are called ceramics.
2. What is glazing?
The process of manufacturing the clay product into non porous shining material is called glazing.
3. Name the raw materials used for the manufacture of ceramics.
a. Clay like kaolinite and bentonite.
b. Flint
c. White clay
d. Quartz
e. Feldspar
4. What are kaolinite and bentonite?
Kaolinite and bentonite are different types of clay used in the manufacture of ceramics.
5. Write any one similarity between glass and ceramics.
Both glass and ceramic materials are brittle.
6. What are the advantages of ceramic pots over ordinary clay pots?
Ordinary clay pots are porous and they have a dull, unattractive surface. Ceramic pots are made non- porous and attractive by glazing. Ceramic pots can be given attractive colours also.
7. Which oxides are used to make coloured ceramics
Metallic oxides
8. Write the properties of ceramics
a. Ceramics are brittle
b. Ceramics are heat resistant
c. Ceramics are bad conductor of electricity
d. Ceramics are non-corrosive to chemicals.
e. Ceramics are good insulators of electricity.
f. Ceramics can be given a glossy finish and attractive colours.
g. Ceramics have high compressive strength.
9. What is feldspar?
Naturally occurring aluminium silicate mineral containing sodium, potassium in combined form similar to clay minerals is known as feldspar.
10. What is porcelain? What are the materials used for preparing porcelain?
Porcelain is a commonly used synthetic material mainly made from clay.
Porcelain is prepared by using white clay, feldspar and sand (quartz).
11. What is chinaware? Where are they generally used? Why?
Dishware’s made of high quality porcelain are called chinaware. They are used in laboratories in the form of china dish.
Chinaware is heat-resistant and non-corrosive to chemicals. This is why they are used in the laboratory
12. Unglazed ceramic materials are used in water filters. Give reason.
Unglazed ceramic materials are highly porous. Therefore, they can be used to filter water
13. What is clay? State any two uses of clay.
Clay is a naturally occurring but thermally setting substance which can be moulded to any desired shape. Chemically, clay is a complex mixture of silicates.
Clay is exclusively used to make cooking vessels, roof tiles and decorative items.
14. What are the steps involved in the making of ceramic wares?
The steps involved in the making of ceramic wares are:
1) Selection of appropriate raw materials
2) Shaping the mix into the needed form
3) Drying and firing.
15. What is firing of ceramic materials?
The process of application of fire or heat in order to harden or to give glaze to ceramic materials during their manufacture is known as firing.
16. How ceramic wares are made attractive?
Ceramic wares are made attractive in two ways:
1. By glazing the article.
2. By giving it an attractive colour by addition of a suitable metal oxide.
17. Why are kaolinite and bentonite generally used for manufacturing ceramics?
Kaolinite and bentonite are forms of clay. They can be given any desired shape easily. Therefore, they are used to manufacture ceramic materials
18. How is the cracking of ceramic articles controlled?
The cracking of ceramic articles is controlled to some extent by adding non-day materials such as flint and quartz to the mix while making ceramics:
19. How does adding non-clay materials like flint and quartz to the mix help to avoid cracks in ceramic materials?
Flint and quartz are different forms of silica which do not absorb water, their presence in the mix used to make ceramics will help to prevent cracks because they do not absorb water and hence do not get transformed on heating. Hence, they do not shrink on heating.
20. Why are the pottery made from a mix of clay and flint (or quartz) porous?
During the manufacture of pottery from a mix of clay and flint, water escapes from clay and leaves tiny empty spaces that get filled up with air. This makes the material porous,
21. Mention some of the chemicals used for glazing porcelain articles.
Chemicals like boron, alumina and smooth silica and insoluble sulphates are used to provide glazing to porcelain articles
22. Explain the manufacture of ceramics.
Once the appropriate raw materials are chosen to get the desired finished, next step is shaping these into the needed form. This is followed by drying and firing of the shaped article which stabilises the shape. Thus, the sequence shaping-drying-firing is the characteristic of all the ceramics.
On heating the ceramic materials, at about 1073K to 1273K, they melt into a glass like, liquid, which fill the pores between individual clay particles and strengthens their contact points. On cooling, this glossy material gives a shining and smooth finish to the material.
Ceramic articles get coloured tinge due to the presence of some metallic oxides in the raw materials used.
23. Write the uses of ceramics
a. Ceramics are good at stopping the flow of electricity.
b. Ceramics are used in electrical gadgetry.
c. Ceramic balls can be used to replace steel in ball bearings
d. Work is being done in developing ceramic spare parts for gas turbine engines.
e. Recent advances have been made in ceramics which include bioceramics, such as dental implants and synthetic bones.
24. Make a list of some commonly used articles made of porcelain and other ceramics.
Cups, saucers plates, pots, jars, flower vases, floor tiles, sanitary ware and decorative items are some of the articles made of ceramics. Ceramic materials are also used as construction materials like bricks, insulating materials and grinding materials
25. List any four industrial applications of ceramics.
Ceramics are widely used in electronic, electrical, mechanical, aerospace, chemicals, textiles and many other fields. Ceramic balls are now replacing steel ball bearings in machines. Ceramics are good insulators. This property is used in electrical gadgetry. Efforts are on to develop ceramic spare parts for automobiles and turbine engines. Ceramic materials are used in dental implants and synthetic bones.
26. Ceramics have ability to withstand high temperature.
27. China dish used in laboratories are heat resistant.
28. Unglazed ceramic materials are used in water filters.
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