Limestone is a naturally occuring form of calcium carbonate. It is used as building materials and also for manufacture of other building materials such as portland cement. It is used for the production of quickline and slaked lime which have wide applications in chemical, metallugical and construction industry. The pure `CaCO_(3)`, called precipitated calcium carbonate, is used extensively as filler, providing bulk to materials such as paint, plastics, printing links and rubber. it is also used in toothpastes, cosmetics and antacids. Quicklime and slaked lime are the cheapest and the most widely used bases for neutralising unwanted acids. Lime is used to neutralise acidic soils. An important application of quicklime is in air pollution control for the removal of `SO_(2)` in electric power plants. slaked lime is used in the manufature of other alkalis and bleacing powder, in sugar refinig, in tanning hide and in water softening.
Quiclime is

Options

A. `CaO`
B. `CaCO_(3)`
C. `Ca(OH)_(2)`
D. `CaSO_(4)`

Answer

To answer the question "Quicklime is:", we will follow a step-by-step approach to understand what quicklime is and its chemical composition.

### Step-by-Step Solution:

1. **Identify Quicklime**: Quicklime is a term commonly used to refer to a specific chemical compound.

**Hint**: Think about the common names used in chemistry for compounds.

2. **Chemical Composition**: Quicklime is chemically known as calcium oxide.

**Hint**: Recall the chemical formula for calcium oxide.

3. **Chemical Formula**: The chemical formula for calcium oxide is \( \text{CaO} \).

**Hint**: Remember that the symbol for calcium is \( \text{Ca} \) and for oxygen is \( \text{O} \).

4. **Properties of Quicklime**: Quicklime is a white, caustic, and alkaline substance. It is crystalline at room temperature.

**Hint**: Consider the physical properties of substances and how they relate to their uses.

5. **Uses of Quicklime**: Quicklime has various applications, including in construction, air pollution control, and as a neutralizing agent for acids.

**Hint**: Think about the industries that utilize quicklime and its role in those processes.

### Final Answer:
Quicklime is calcium oxide, represented by the chemical formula \( \text{CaO} \).

### Summary:
- Quicklime = Calcium Oxide
- Chemical Formula = \( \text{CaO} \)
- Properties = White, caustic, alkaline, crystalline
- Applications = Construction, air pollution control, neutralizing acids