Question

The formula of quicklime is:
A. $Ca{(OH)_2}$
B. $CaC{l_2}$
C. $CaO$
D. $CaS{O_4}$

Answer 1

We need to know that the Quick lime is a chemical compound. Quick lime is crystalline solid at room temperature. It is white, caustic and alkaline compound. Quick lime is prepared by the thermal decomposition of materials, such as limestone. Limestone contains calcite minerals. This process is called calcination.

Complete step by step answer:
We must know that the Quick lime is also known as burnt lime or calcium oxide. The term lime is used broadly and it connotes (suggest in addition to the literal) inorganic materials. The materials are oxides, carbonates and hydroxides of calcium, aluminium and iron, etc.
Preparation of quick lime is,
$CaC{O_{3(s)}} \to Ca{O_{(S)}} + C{O_2}$
The chemical formula of calcium carbonate (also known as lime), $CaC{O_3}$ is heated at above $825^\circ C$ . The above process is also known as lime-burning. The above process liberates carbon dioxide and leaves quicklime. Quick lime $(CaO)$ is not stable. When quicklime cooled, it spontaneously reacted with carbon dioxide from the atmosphere and converted back to $CaC{O_3}$, if-not then quick lime quenched with water to set as lime mortar (composed of lime and an aggregate sand).
Quick lime reacts with water to form slaked lime or lime water (calcium hydroxide),
$CaO + {H_2}O \to Ca{(OH)_2}$
Aqueous solution of calcium hydroxide is known as lime water, at room temperature it is sparingly soluble in water.
Now we have the clear idea about quicklime and lime water.

Hence the correct option is C.

Note: Not to be confused between quick lime, lime water and lime. Quick lime is employed in preference to calcium hydroxide at oil mud mixing plants because it generates heat when it becomes slaked with water and thus accelerates emulsification by the reaction to form calcium fatty-acid soap. Quick lime is a relatively inexpensive one.