This set of Building Construction Multiple Choice Questions & Answers (MCQs) focuses on “Glass – 2”.
1. Litharge is _________
a) Lead trioxide
b) Lead sesquioxide
c) Lead dioxide
d) Lead monoxide
Explanation: Litharge is lead monoxide which is one of the raw materials needed to manufacture potash-lead glass. Other raw materials required are potassium carbonate and pure sand.
2. Which of the following is a raw material for common glass?
a) Lead dioxide
b) Potassium bicarbonate
c) Salt cake
Explanation: The main raw materials required to manufacture common glass are salt cake, chalk, coke and ordinary sand. The chemical formula of salt cake is Na2SO4.
3. _______ is used to indicate pieces of broken glass or waste glass.
a) Sodium bicarbonate
Explanation: For all the types of glass, in addition to the raw materials, cullets and decolorizers are also added. Cullet is used to indicate pieces of broken glass or waste glass.
4. Common glass is mainly a mixture of ___________
a) Calcium silicate, potassium silicate and copper silicate
b) Sodium silicate, iron silicate and calcium silicate
c) Aluminium silicate, potassium silicate and iron silicate
d) Magnesium silicate, potassium silicate and zinc silicate
Explanation: Common glass is mainly a mixture of sodium silicate, iron silicate and calcium silicate. It is usually available in green, brown or yellow colour.
5. Ferric oxide gives a very light yellow tint to the glass while ferrous oxide imparts a green colour.
Explanation: The raw materials required to manufacture glass usually contain traces of compounds of iron. Ferric oxide gives a very light yellow tint to the glass while ferrous oxide imparts a green colour. Decolorizers are added in order to avoid such effects.
6. Which of the following substances is not used as a decolorizer in the manufacturing of glass?
a) Potassium carbonate
b) Antimony oxide
c) Cobalt oxide
d) Manganese dioxide
Explanation: Potassium carbonate is a raw material needed to manufacture potash-lime glass and potash-lead glass. Decolorizers are substances which are added to glass in addition to the raw materials in order to avoid any colouring effects due to the presence of iron compounds in the glass. Some of the examples of decolourisers are antimony oxide, manganese dioxide and cobalt oxide.
7. The process of slow and gradual cooling of glass articles is known as _________
Explanation: The process of slow and gradual cooling of glass articles is known as annealing. There are two methods of annealing of glass. These are flue treatment and oven treatment.
8. Glass can be made opaque by grinding the surface of the glass with _________
Explanation: Glass can be made opaque by grinding the surface of the glass with emery. It can also be done chemically by applying hydrochloric acid.
9. In the silvering of glass, a thin coat of ______ is first applied on which silver is then deposited.
Explanation: In the silvering of glass, a thin coat of tin is first applied on which silver is then deposited. Then, a suitable paint is applied in order to protect it against atmospheric effects.
10. Which of the following is added to the glass in order to make its colour violet?
a) Ferric oxide
b) Manganese dioxide
c) Tin oxide
d) Copper oxide
Explanation: Colouring pigments are added to the raw materials while manufacturing of the glass in order to make coloured glass. Manganese dioxide is added to the glass in order to make its colour violet.
11. Which of the following is added to the glass in order to make its colour green?
a) Cobalt oxide
b) Magnesium dioxide
c) Sodium oxide
d) Chromium sesquioxide
Explanation: Chromium sesquioxide is added to the glass in order to make its colour green. Ferric oxide is also added along with it. The coloured glass is used for many purposes such as window panels, decorative tiles, etc.
12. Alternate layers of ________ plastic is present in bullet-proof glass.
c) Methyl methacrylate
Explanation: Bullet-proof glass is made of many layers of plate glass. Alternate layers of vinyl-resin plastic are present in this type of glass. This glass does not allow the bullet to pierce through it.
13. Which of the following is not true about fibreglass?
a) Fibreglass is soft to touch
b) Fibreglass is flexible
c) Fibreglass readily absorbs water
d) Fibreglass is fire-proof
Explanation: Fibreglass consists of minute glass rods. Fibreglass is fire-proof and soft to touch. This type of glass is flexible in nature. Also, it does not absorb water.
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