Building Construction Multiple Choice Questions & Answers (MCQs) on “Glass – 2”.
1. Litharge is _________
a) Lead trioxide
b) Lead sesquioxide
c) Lead dioxide
d) Lead monoxide
Answer: d
Clarification: 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
d) Litharge
Answer: c
Clarification: 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
b) Cullet
c) Decolorizer
d) Sand
Answer: b
Clarification: 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
Answer: b
Clarification: 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.
a) True
b) False
Answer: a
Clarification: 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
Answer: a
Clarification: 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 _________
a) Pressing
b) Rolling
c) Annealing
d) Spinning
Answer: c
Clarification: 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 _________
a) Mortar
b) Flint
c) Alcohol
d) Emery
Answer: d
Clarification: 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.
a) Tin
b) Zinc
c) Iron
d) Copper