How Is Slaked Lime Prepared and What Are Its Common Uses?
Slaked lime is a key inorganic compound, scientifically known as calcium hydroxide. This versatile material finds widespread application in construction, agriculture, and chemical processes. Also recognized as hydrated lime, slaked lime is produced by reacting quicklime with water—a reaction that yields a fine, white powder. Understanding slaked lime’s properties, formula, and main uses helps highlight its significance across various fields and industries.
Slaked Lime: Definition and Formula
Slaked lime meaning refers to the product obtained when calcium oxide (quicklime) reacts with water. This reaction is highly exothermic and is represented by a simple chemical equation. The resulting compound, slaked lime powder, is widely used for its alkaline nature and chemical reactivity.
Chemical Formula & Reaction
- The slaked lime formula is \( Ca(OH)_2 \), representing calcium hydroxide.
- Formation reaction:
$$ CaO\; (quicklime) + H_2O \rightarrow Ca(OH)_2\; (slaked\; lime) $$
Physical Properties of Slaked Lime
Calcium hydroxide, or slaked lime, appears as a soft, white powder or crystal. Its solubility and alkaline nature are central to many of its uses.
- Color: White
- State: Powdery solid (sometimes in suspension as "milk of lime")
- Solubility: Sparingly soluble in water; forms an alkaline solution called limewater
- Odor: Odorless
- Taste: Alkaline, bitter
Major Uses of Slaked Lime
The utility of slaked lime is evident in multiple sectors due to its unique chemical behavior and cost-effectiveness.
Key Applications
- Construction: Used in making slaked lime paint and lime mortar for masonry and plastering
- Agriculture: Neutralizes acidic soils and provides calcium nutrients; commonly applied as slaked lime for trees to prevent fungal infections
- Water Treatment: Softens water and removes impurities
- Chemical Industry: Key role in manufacturing bleaching powder, caustic soda, and as a neutralizing agent
- Sanitation: Used to treat industrial and domestic wastewater
- Food Industry: Serves as a food additive for pickling and processing sugar
Availability and Historical Significance
Slaked lime is easily obtainable as slaked lime powder from local suppliers, building material stores, and online retailers. Searches like slaked lime near me or slaked lime home depot highlight its commercial accessibility.
- Ancient Material: Used since antiquity in construction and sanitation
- "Lime" in building: The word "lime" historically refers to both quicklime and slaked lime for mortars and whitewashes
Safety Considerations
Calcium hydroxide should be handled with care due to its alkaline and caustic nature.
- Wear gloves and protective gear when handling
- Avoid inhalation of powder and contact with eyes or skin
In summary, slaked lime (\( Ca(OH)_2 \)) is a vital compound with vast industrial, agricultural, and household uses. It is valued for making slaked lime paint, soil amendment, water purification, and more. From finding slaked lime for sale to using it in daily life, this compound continues to play an essential role—much like other fundamental materials discussed in topics such as metals and their properties, fluid behavior, and the thermal characteristics of materials. Understanding slaked lime’s properties ensures informed and safe usage, echoing its relevance from ancient to modern times—including contexts as diverse as materials science and even simulations like slaked lime vintage story.
FAQs on What Is Slaked Lime? Uses, Preparation, and Properties
1. What is slaked lime?
Slaked lime, also known as calcium hydroxide (Ca(OH)₂), is a white, slightly soluble, alkaline solid made when water is added to quicklime (calcium oxide, CaO).
Key points:
- Formed by the reaction: CaO + H₂O → Ca(OH)₂
- Commonly called hydrated lime or milk of lime when in suspension
- Used in construction, agriculture, and water treatment
2. How is slaked lime prepared?
Slaked lime is prepared by adding water to quicklime (CaO) in a controlled reaction called slaking.
Preparation steps:
- Obtain calcium oxide (quicklime)
- Slowly add water (H₂O) to quicklime
- The exothermic reaction forms calcium hydroxide (Ca(OH)₂)
3. What are the uses of slaked lime?
Slaked lime is widely used in various industries due to its alkaline nature and versatility.
Major uses include:
- Neutralizing acidic soils in agriculture
- As a key ingredient in whitewashing walls
- Treating wastewater and purifying water
- In making building materials like mortar and plaster
4. What is the chemical formula and structure of slaked lime?
The chemical formula of slaked lime is Ca(OH)₂. It consists of a central calcium ion (Ca²⁺) bonded with two hydroxide ions (OH⁻).
- Formula: Ca(OH)₂
- Structure: Each Ca²⁺ associates with two OH⁻ ions
5. What is the difference between quicklime and slaked lime?
The main difference is that quicklime (CaO) is made by heating limestone, while slaked lime (Ca(OH)₂) is produced by adding water to quicklime.
Key differences:
- Quicklime: CaO, white, highly reactive, made by heating CaCO₃
- Slaked lime: Ca(OH)₂, softer, forms when CaO reacts with water
6. Write the reaction between quicklime and water to form slaked lime.
When quicklime (CaO) reacts with water, it forms slaked lime (Ca(OH)₂).
Reaction:
CaO (s) + H₂O (l) → Ca(OH)₂ (s)
- This reaction is exothermic (produces heat)
7. Why is slaked lime used in whitewashing?
Slaked lime is used in whitewashing because it forms a smooth, bright, and disinfectant coating on walls.
Benefits include:
- It slowly reacts with CO₂ to form calcium carbonate, giving a durable, shiny finish
- Provides an antibacterial, hygienic layer
- Cost-effective and easy to apply
8. What are the safety precautions while handling slaked lime?
When handling slaked lime, safety precautions are essential due to its alkaline and irritant nature.
Important precautions:
- Wear gloves, goggles, and protective clothing
- Avoid inhaling dust
- Wash skin thoroughly if contact occurs
- Handle in a well-ventilated area
9. Is slaked lime soluble in water?
Slaked lime (Ca(OH)₂) is only slightly soluble in water, forming a suspension known as lime water.
- Solubility increases slightly with cold water
- Lime water is used as a test for carbon dioxide
10. What happens when carbon dioxide is passed through slaked lime solution?
Passing carbon dioxide (CO₂) through slaked lime solution (lime water) forms a milky white precipitate of calcium carbonate (CaCO₃).
Reaction:
Ca(OH)₂ + CO₂ → CaCO₃ + H₂O
- This reaction is used as a test for CO₂ gas
