Calcium hypochlorite (Ca(ClO)2) is a chemical compound commonly used as a disinfectant and bleaching agent. It’s effective in killing bacteria, viruses, and algae in water treatment and sanitation.
| IUPAC Name | Calcium hypochlorite |
| Molecular Formula | Ca(ClO)2 |
| CAS Number | 7778-54-3 |
| Synonyms | Hypochlorous acid calcium salt, Bleaching powder, Chlorinated lime, Calcium oxychloride, HTH, Cal hypo |
| InChI | InChI=1S/Ca.2ClO/c;21-2/q+2;2-1 |
Calcium Hypochlorite Properties
Calcium Hypochlorite Formula
Calcium hypochlorite has the chemical formula Ca(ClO)2. It is a white crystalline solid that has a strong chlorine odor. The formula of calcium hypochlorite shows that it contains one Ca+2 ion and two ClO- ions. The hypochlorite ion has a negative charge and is responsible for the strong oxidizing properties of the compound.
Calcium Hypochlorite Molar Mass
The molar mass of Ca(ClO)2 is 142.98 g/mol. It is calculated by adding the atomic masses of calcium, chlorine, and oxygen present in one molecule of Ca(ClO)2. The molar mass of Ca(ClO)2 is an important parameter that is used in various chemical calculations.
Calcium Hypochlorite Boiling Point
Ca(ClO)2 decomposes before it reaches its boiling point. Therefore, it does not have a well-defined boiling point. When Ca(ClO)2 is heated, it undergoes thermal decomposition to form calcium chloride, oxygen, and chlorine gas.
Calcium Hypochlorite Melting Point
The melting point of Ca(ClO)2 is 100 °C. At this temperature, Ca(ClO)2 melts to form a clear liquid. Ca(ClO)2 is highly soluble in water, and when it dissolves in water, it releases hypochlorite ions, which makes it an effective disinfectant.
Calcium Hypochlorite Density g/mL
The density of Ca(ClO)2 is 2.35 g/mL. It is a relatively dense compound and is heavier than water. The high density of Ca(ClO)2 is due to the presence of calcium ions in its crystal lattice.
Calcium Hypochlorite Molecular Weight
The molecular weight of Ca(ClO)2 is 142.98 g/mol. It is calculated by adding the atomic masses of calcium, chlorine, and oxygen present in one molecule of Ca(ClO)2. The molecular weight of Ca(ClO)2 is an important parameter that is used in various chemical calculations.
Calcium Hypochlorite Structure
Ca(ClO)2 has a crystalline structure. The crystal lattice of Ca(ClO)2 is composed of Ca+2 ions and ClO- ions. The ClO- ions are arranged in a tetrahedral geometry around the Ca+2 ions. The crystal lattice structure of Ca(ClO)2 gives it its strong oxidizing properties.
Calcium Hypochlorite Solubility
Ca(ClO)2 is highly soluble in water. It dissolves in water to form a hypochlorite ion and a calcium ion. The solubility of Ca(ClO)2 in water increases with increasing temperature. Ca(ClO)2 is also soluble in organic solvents such as acetone and ethanol.
| Appearance | White crystalline solid |
| Specific Gravity | 2.35 |
| Color | White |
| Odor | Chlorine-like odor |
| Molar Mass | 142.98 g/mol |
| Density | 2.35 g/cm³ |
| Melting Point | 100 °C |
| Boiling Point | Decomposes before boiling |
| Flash Point | Not applicable |
| Water Solubility | 21 g/100 mL (20°C) |
| Solubility | Soluble in acetone, ethanol, glycerol, and water |
| Vapour Pressure | Not applicable |
| Vapour Density | Not applicable |
| pKa | 7.5 |
| pH | ~11 |
Calcium Hypochlorite Safety and Hazards
Ca(ClO)2 can be hazardous if not handled properly. It is a strong oxidizer and can react violently with organic compounds, releasing toxic gases. It can cause skin and eye irritation, and prolonged exposure can lead to respiratory problems. It should be stored in a cool, dry, and well-ventilated area away from organic materials, reducing agents, and acids. Ca(ClO)2 should be handled with care and protective gear, such as gloves and goggles, should be worn during its handling. It should not be mixed with other chemicals, especially acids or reducing agents, as it can cause an explosion.
| Hazard Symbols | O, Xi, N |
| Safety Description | Harmful if swallowed, causes skin irritation, causes serious eye irritation, may cause cancer |
| UN IDs | UN1748 |
| HS Code | 2828.90.00 |
| Hazard Class | 5.1 (Oxidizing agents) |
| Packing Group | II |
| Toxicity | LD50 (oral, rat) = 850 mg/kg; LC50 (inhalation, rat) = 10.8 mg/m³ (4-hour exposure) |
Calcium Hypochlorite Synthesis Methods
There are several methods for synthesizing Ca(ClO)2.
One method involves mixing chlorine gas with slaked lime, also known as calcium hydroxide, in water. The reaction produces Ca(ClO)2, calcium chloride, and water. Another method involves reacting chlorine gas with dry calcium hydroxide, which yields Ca(ClO)2 and water vapor.
The process of producing Ca(ClO)2 on a large scale commonly involves reacting sodium hypochlorite with calcium chloride, which generates Ca(ClO)2 and sodium chloride.
Another method involves reacting calcium carbonate with chlorine gas in the presence of water or acetic acid. The reaction produces Ca(ClO)2, carbon dioxide, water or calcium acetate, and hydrochloric acid.
These methods require careful handling and proper equipment to ensure safety and efficiency. The choice of method depends on the scale of production and the desired purity of the final product.
Calcium Hypochlorite Uses
Ca(ClO)2 has a wide range of uses due to its strong oxidizing and disinfecting properties. Here are some common uses of Ca(ClO)2:
- Water treatment: Widely used to disinfect water in swimming pools, drinking water systems, and wastewater treatment plants.
- Bleaching agent: Used as a bleaching agent for cotton, linen, and pulp, as well as in the manufacturing of paper and textiles.
- Sanitization: Commonly used to sanitize surfaces and equipment in the food and beverage industry.
- Deodorization: Used to remove unpleasant odors from fabrics, carpets, and other materials.
- Disinfectant: Effective disinfectant for hospitals, laboratories, and other healthcare facilities.
- Algae control: Used to control the growth of algae in bodies of water, such as ponds and lakes.
- Chemical synthesis: Used in the synthesis of various organic and inorganic compounds.
- Household use: Used as a household disinfectant, especially for cleaning and disinfecting toilets and drains.
- Oil well drilling: Also used in oil well drilling to prevent the growth of bacteria and other microorganisms.
Questions:
Q: Can you use calcium hypochlorite to remove a tattoo?
A: No, Ca(ClO)2 should not be used to remove a tattoo. It is a strong oxidizing agent and can cause severe skin damage and scarring.
Q: How to store calcium hypochlorite?
A: Ca(ClO)2 should be stored in a cool, dry, and well-ventilated area away from direct sunlight, heat sources, and incompatible substances. It should be kept in a tightly closed container and away from moisture and water.
Q: Where to buy calcium hypochlorite?
A: Ca(ClO)2 can be purchased from chemical supply companies, pool supply stores, and online retailers.
Q: How much calcium hypochlorite for drinking water?
A: The amount of Ca(ClO)2 required for drinking water treatment depends on the concentration of the solution and the volume of water being treated. The recommended dosage is usually between 0.2 and 0.5 ppm (parts per million) for regular disinfection.
Q: How much calcium hypochlorite is safe to ingest?
A: Ca(ClO)2 should never be ingested, as it is highly toxic and can cause severe health problems or even death.
Q: Calcium hypochlorite water purification?
A: Ca(ClO)2 is commonly used for water purification and disinfection in various settings, including swimming pools, drinking water systems, and wastewater treatment plants.
Q: Calcium hypochlorite shock?
A: Ca(ClO)2 shock is a process of adding a higher concentration of Ca(ClO)2 to a pool or spa to quickly raise the chlorine levels and eliminate harmful bacteria and contaminants.
Q: Calcium hypochlorite to disinfect water?
A: Ca(ClO)2 is a powerful disinfectant that is often used for water treatment and purification to eliminate bacteria, viruses, and other harmful microorganisms.
Q: Is Ca(OCl)2 an acid or base?
A: Calcium hypochlorite (Ca(OCl)2) is a base, as it can accept a proton to form a hydroxide ion.
Q: What is the reduced form of Ca(OCl)2 that remains at the end of the experiment?
A: The reduced form of Ca(OCl)2 that remains at the end of an experiment depends on the specific reaction taking place. In some cases, it may be calcium chloride (CaCl2) or calcium carbonate (CaCO3).