Building Construction Multiple Choice Questions & Answers (MCQs) on “Lime – 1”.
1. The process of heating to redness in the presence of air is called __________
a) Hydraulicity
b) Setting
c) Roasting
d) Calcination
Answer: d
Clarification: The process of heating to redness in the presence of air is called calcination. Hydraulicity is the property of lime by which it sets in damp places or thick masonry walls where the free circulation of air is absent.
2. Lime is obtained from the calcination of ___________
a) Lime-silica
b) Sandstone
c) Limestone
d) Lime-concrete
Answer: c
Clarification: Lime is obtained from the calcination of limestone. Carbon dioxide and moisture are removed from it due to calcination and the product which remains is called lime.
3. The chemical composition of quick lime is ____________
a) CaS
b) CaO
c) MgO
d) MgS
Answer: b
Clarification: The chemical composition of quick lime is CaO. It is obtained by calcination of relatively pure limestone. Quick lime has a great affinity for moisture.
4. Slaked lime is __________
a) Calcium oxide
b) Hydrated oxide of calcium
c) Calcium carbonate
d) Calcium silicate
Answer: b
Clarification: Slaked lime is the hydrated oxide of calcium. It is obtained by slaking of lime. Slaking is the process of adding a sufficient quantity of water to quick lime to form a white powder called slaked lime.
5. Acid-resistant cement and gypsum are examples of _________ materials.
a) Air binding
b) Hydraulic binding
c) Autoclave binding
d) Sound binding
Answer: a
Clarification: The binding materials are classified into three categories – air binding materials, autoclave binding materials and hydraulic binding materials. Acid-resistant cement and gypsum are examples of air binding materials.
6. Which of the following is an autoclave binding material?
a) Quick lime
b) Hydraulic lime
c) Gypsum
d) Lime-silica
Answer: d
Clarification: Autoclave binding materials are also called autoclave-setting substances. Lime-silica is an example of autoclave binding material. Quick lime and gypsum are examples of air binding materials. Hydraulic lime is an example of hydraulic binding material.
7. Kankar is an impure limestone while white chalk is pure limestone.
a) True
b) False
Answer: a
Clarification: Lime generally does not occur in the free state in nature. The major source of obtaining lime is limestones obtained from nature. Kankar is an impure limestone while white chalk is pure limestone.
8. In order to develop hydraulicity, it is necessary to have _________ and _________ present in chemical combination with the limestone.
a) Alumina and carbon
b) Magnesium and carbon
c) Silica and carbon
d) Alumina and silica
Answer: d
Clarification: In order to develop hydraulicity, it is necessary to have alumina and silica present in chemical combination with the limestone. Silicates of magnesium, aluminium and calcium are responsible for hydraulicity.
9. Which of the following is not a property of fat lime?
a) It readily hardens
b) The colour of fat lime is perfectly white
c) Fat lime slakes vigorously
d) Fat lime sets slowly in the presence of air