Calcium bisulfite (Ca(HSO3)2) is a compound made up of calcium, sulfur, and oxygen. It is commonly used as a food preservative and an antioxidant in the food industry.
| IUPAC Name | Calcium hydrogen sulfite |
| Molecular Formula | Ca(HSO3)2 |
| CAS Number | 13780-03-5 |
| Synonyms | Calcium bisulphite, Calcium hydrogen sulfite, Calcium sulfurous acid, Bisulfite of lime |
| InChI | InChI=1S/Ca.2H2O3S/c;2*1-4(2)3/h;(H2,1,2,3)/q+2;;/p-2 |
Calcium Bisulfite Properties
Calcium Bisulfite Formula
The chemical formula for calcium bisulfite is Ca(HSO3)2. It indicates the number and type of atoms in a molecule or formula unit. The formula is important in determining the molecular weight, molar mass, and other properties of the compound. Ca(HSO3)2 is an important compound used in the food industry as a preservative and antioxidant.
Calcium Bisulfite Molar Mass
Ca(HSO3)2 has a molar mass of 202.2 g/mol. It is an ionic compound made up of calcium, hydrogen sulfite, and sulfur dioxide. The molar mass is important for calculating the amount of Ca(HSO3)2 needed in a reaction or for preparing a solution of a desired concentration.
Calcium Bisulfite Boiling Point
The boiling point of Ca(HSO3)2 is not a well-defined value because it decomposes before reaching its boiling point. Ca(HSO3)2 decomposes releasing sulfur dioxide gas. Therefore, it is not used in processes that require high-temperature applications.
Calcium Bisulfite Melting Point
The melting point of Ca(HSO3)2 is 203°C. At this temperature, it decomposes to form calcium sulfate and sulfur dioxide. The decomposition of Ca(HSO3)2 is an exothermic reaction and produces a large amount of heat. Therefore, it should be handled with care when heated.
Calcium Bisulfite Density g/mL
The density of Ca(HSO3)2 varies depending on the form it is in. The anhydrous form of Ca(HSO3)2 has a density of 2.68 g/mL, while the dihydrate form has a density of 1.98 g/mL. The density of a substance is important in determining the amount of substance needed to fill a certain volume.
Calcium Bisulfite Molecular Weight
The molecular weight of Ca(HSO3)2 is 202.2 g/mol. It is calculated by adding the atomic weights of the constituent elements: calcium (40.08 g/mol), hydrogen (1.008 g/mol), sulfur (32.06 g/mol), and oxygen (15.99 g/mol). The molecular weight is important in determining the amount of substance needed in a reaction.
Calcium Bisulfite Structure
The structure of Ca(HSO3)2 is an ionic compound with the chemical formula Ca(HSO3)2. It has a tetrahedral shape with a central calcium atom surrounded by four oxygen atoms. The hydrogen sulfite ions are bonded to the calcium atom through ionic bonds. The structure of Ca(HSO3)2 is important in understanding its chemical properties.
Calcium Bisulfite Solubility
Ca(HSO3)2 is moderately soluble in water, with a solubility of approximately 60 grams per 100 milliliters of water at room temperature. Its solubility increases with temperature, and it is also soluble in ethanol and glycerol.
| Appearance | White crystalline powder |
| Specific Gravity | 2.68 (anhydrous), 1.98 (dihydrate) |
| Color | White |
| Odor | Odorless |
| Molar Mass | 202.2 g/mol |
| Density | 2.68 g/mL (anhydrous), 1.98 g/mL (dihydrate) |
| Melting Point | 203°C |
| Boiling Point | Decomposes |
| Flash Point | Not applicable |
| Water Solubility | Soluble |
| Solubility | Soluble in water, insoluble in organic solvents |
| Vapor Pressure | Not applicable |
| Vapor Density | Not applicable |
| pKa | 1.92 |
| pH | 4.5-6.0 |
Calcium Bisulfite Safety and Hazards
Ca(HSO3)2 is generally considered safe when used in small quantities in food products. However, it can be hazardous if not handled properly. It can cause skin irritation, eye irritation, and respiratory problems if it is inhaled. Ingestion of large amounts can cause gastrointestinal upset, including nausea and vomiting. Ca(HSO3)2 should be handled with care and protective equipment, such as gloves and a respirator, should be worn when working with it. It should be stored in a cool, dry place away from heat and incompatible materials. Spills should be cleaned up immediately to prevent exposure to the substance.
| Hazard Symbols | None |
| Safety Description | Avoid inhalation, ingestion and skin/eye contact. Wear protective equipment. |
| UN IDs | Not regulated |
| HS Code | 28321000 |
| Hazard Class | Not classified |
| Packing Group | Not applicable |
| Toxicity | Low toxicity, but can cause skin and eye irritation, respiratory problems, and gastrointestinal upset if ingested in large amounts. |
Calcium Bisulfite Synthesis Methods
Several methods can synthesize Ca(HSO3)2.
One method involves reacting sulfur dioxide gas with calcium hydroxide, which produces Ca(HSO3)2 and water.
The method involves reacting calcium oxide with sulfur dioxide gas, generating calcium sulfite. Then, reacting sulfur dioxide gas with calcium sulfite produces Ca(HSO3)2.
Reacting sulfur dioxide gas with water and calcium carbonate produces Ca(HSO3)2, carbon dioxide gas, and water.
To synthesize Ca(HSO3)2 in a laboratory setting, one can add sulfur dioxide gas to a solution of calcium hydroxide or calcium oxide until the desired pH is achieved. The resulting solution will contain Ca(HSO3)2, which can be purified through filtration or precipitation methods.
Calcium Bisulfite Uses
Ca(HSO3)2 has several uses in various industries due to its unique properties. Here are some of the most common uses of Ca(HSO3)2:
- Food industry: Used as a food preservative to prevent the growth of bacteria and other microorganisms in food products, especially in fruits and vegetables.
- Water treatment: Used in water treatment to remove excess chlorine and other chemicals from the water, and to prevent the growth of bacteria and algae in water systems.
- Textile industry: Used in the textile industry to remove excess dye from fabric and to prevent discoloration during the dyeing process.
- Paper industry: Used in the paper industry to bleach pulp and prevent discoloration of paper products.
- Chemical industry: Used in the chemical industry as a reducing agent and as a source of sulfur dioxide gas.
- Pharmaceutical industry: Used in the pharmaceutical industry as an antioxidant and preservative in certain medications.
Questions:
Q: Does the European Food Safety Authority approve of calcium bisulfite?
A: Yes, the European Food Safety Authority (EFSA) has approved the use of Ca(HSO3)2 as a food additive. It is listed as an approved food preservative in the European Union.
Q: What is the E number of calcium bisulfite?
A: The E number of Ca(HSO3)2 is E227. The E number is a code assigned to food additives by the European Union.
Q: Is calcium bisulfite safe?
A: Ca(HSO3)2 is generally considered safe for consumption in small amounts. However, it can cause skin and eye irritation, respiratory problems, and gastrointestinal upset if ingested in large amounts. It is important to handle and store Ca(HSO3)2 properly to ensure its safety.
Q: What is the solubility of calcium bisulfite in water?
A: Ca(HSO3)2 is moderately soluble in water, with a solubility of approximately 60 grams per 100 milliliters of water at room temperature.
Q: What are the thermodynamic properties of calcium bisulfite?
A: The thermodynamic properties of Ca(HSO3)2 include a melting point of approximately 150 °C and a boiling point of approximately 160 °C. Its heat capacity and enthalpy of formation have also been studied in various research studies.