D11 Lime Other sources questions

Which compound is used as the raw material for manufacturing lime?

• Calcium carbonate
• Calcium sulphate
• Calcium hydroxide
• Magnesium carbonate

Answer explanation

Calcium carbonate (CaCO₃) is the raw material for lime manufacture, commonly obtained from limestone.

Which of the following is considered an impure limestone used to make hydraulic lime?

• Kankar
• Chalk
• Marble
• Shell lime

Answer explanation

Kankar is a nodular impure limestone rich in clay used to make hydraulic lime.

Which variety of lime is obtained by calcination of sea shells and coral?

• Stone lime
• Shell lime
• Kankar lime
• Magnesium lime

Answer explanation

Shell lime is made from calcination of sea shells and corals, and is very pure.

Which type of lime is known as caustic lime?

• Slaked lime
• Hydrated lime
• Lump lime
• Quick lime

Answer explanation

Quick lime is also called caustic lime and is obtained after calcining limestone.

According to IS:712, which class of lime is used for structural works like arches and domes?

• Class B
• Class A
• Class D
• Class F

Answer explanation

Class A is eminently hydraulic lime used for structural applications under IS:712.

Which class of lime is also known as fat lime?

• Class A
• Class C
• Class D
• Class F

Answer explanation

Class C is fat lime, used for whitewashing and finishing plaster.

What is the percentage of clay required in limestone to develop good hydraulic properties?

• 2–5%
• 10–30%
• 35–40%
• 50–60%

Answer explanation

10–30% clay gives best hydraulic properties to lime.

What is the function of silica when present in free form in limestone?

• Improves setting
• Improves plasticity
• Improves hydraulicity
• Decreases workability

Answer explanation

Silica in combined form improves hydraulicity; in free form it lowers cementing quality.

Which impurity is considered harmful and undesirable for good quality lime?

• Silica
• Pyrites
• Iron oxide
• Clay

Answer explanation

Pyrites are undesirable as they negatively affect lime's setting and durability.

Which test is used to assess the plasticity of lime?

• Soundness test
• Plasticity test
• Ball test
• Workability test

Answer explanation

Plasticity test is performed to assess the moldability and workability of lime.