Sodium bisulfite (NaHSO3) is a chemical compound used as a food preservative and in various industrial applications. It works by inhibiting the growth of bacteria and preventing oxidation.
| IUPAC Name | Sodium hydrogen sulfite |
| Molecular Formula | NaHSO3 |
| CAS Number | 7631-90-5 |
| Synonyms | Sodium bisulphite, Sodium acid sulfite, Sodium hydrogen sulfite, Sodium hydrogen sulphite, Sodium sulfite monohydrate |
| InChI | InChI=1S/Na.H2O3S/c;1-4(2)3/h;(H2,1,2,3)/q+1;/p-1 |
Sodium Bisulfite Properties
Sodium Bisulfite Formula
The chemical formula of sodium bisulfite is NaHSO3. This formula indicates the number and type of atoms present in a single molecule of sodium bisulfite. The formula is crucial in determining the behavior of sodium bisulfite in different chemical reactions and physical conditions.
Sodium Bisulfite Molar Mass
NaHSO3 has a molar mass of 104.06 g/mol. This is the sum of the atomic masses of the constituent elements in a single molecule of NaHSO3. The molar mass is an important physical property that helps to determine the amount of a substance in a given sample.
Sodium Bisulfite Boiling Point
The boiling point of NaHSO3 is 150°C. This is the temperature at which the liquid form of NaHSO3 starts to convert into a gas. The boiling point is a crucial physical property that determines how a substance behaves under different temperature conditions.
Sodium Bisulfite Melting Point
The melting point of NaHSO3 is 150°C. This is the temperature at which the solid form of NaHSO3 starts to convert into a liquid. The melting point is an essential physical property that helps to determine the behavior of a substance under different temperature conditions.
Sodium Bisulfite Density g/mL
The density of NaHSO3 is 1.48 g/mL. This refers to the amount of mass present in a given volume of NaHSO3. Density is an important physical property that helps to determine the behavior of a substance under different pressure and temperature conditions.
Sodium Bisulfite Molecular Weight
The molecular weight of NaHSO3 is 104.06 g/mol. This is the sum of the atomic weights of the constituent elements in a single molecule of NaHSO3. Molecular weight is an essential physical property that helps to determine the amount of a substance in a given sample.
Sodium Bisulfite Structure
NaHSO3 has a molecular structure that consists of one sodium cation (Na+) and one HSO3- anion. The anion consists of one sulfur atom, three oxygen atoms, and one hydrogen atom. The structure of NaHSO3 determines its chemical and physical properties.
Sodium Bisulfite Solubility
NaHSO3 is highly soluble in water, with a solubility of 62 g/100 mL at 20°C. It is also soluble in glycerol and slightly soluble in alcohol. Its solubility in water makes it a useful reagent in various chemical reactions.
| Appearance | White crystalline powder |
| Specific Gravity | 1.48 |
| Color | White to slightly yellow |
| Odor | Sulfurous odor |
| Molar Mass | 104.06 g/mol |
| Density | 1.48 g/mL |
| Melting Point | 150°C |
| Boiling Point | 150°C |
| Flash Point | Not applicable |
| Water Solubility | Very soluble |
| Solubility | Soluble in ethanol |
| Vapor Pressure | Not applicable |
| Vapor Density | Not applicable |
| pKa | 6.97 |
| pH | 4.5-5.5 (5% solution) |
Sodium Bisulfite Safety and Hazards
NaHSO3 can be hazardous if ingested, inhaled, or comes into contact with skin or eyes. It can cause skin irritation, eye damage, respiratory problems, and digestive issues. Prolonged exposure can lead to more severe health problems. It is important to handle and store NaHSO3 with care, using personal protective equipment like gloves, goggles, and respirators. It should be kept away from combustible materials and incompatible substances. In case of accidental contact or ingestion, immediate medical attention should be sought. Proper storage and handling procedures must be followed to prevent any potential hazards.
| Hazard Symbols | Skull and crossbones, Corrosive |
| Safety Description | Avoid contact with skin, eyes, and clothing. Do not ingest or inhale. Use proper protective equipment. |
| UN IDs | UN2693 |
| HS Code | 28321000 |
| Hazard Class | 8 |
| Packing Group | III |
| Toxicity | Highly toxic when ingested or inhaled. Can cause skin and eye irritation, respiratory problems, and digestive issues. Prolonged exposure can lead to severe health problems. |
Sodium Bisulfite Synthesis Methods
There are various methods for synthesizing NaHSO3, but the most common is through the reaction of sodium carbonate and sulfur dioxide.
To produce NaHSO3 solution, mix a solution of sodium carbonate with sulfur dioxide gas. The reaction releases heat and requires a reaction vessel with adequate ventilation.
Another method involves the reaction of sodium hydroxide with sulfur dioxide gas to produce sodium sulfite solution, which is then acidified to produce NaHSO3 solution. For large quantities of NaHSO3, this method proves useful.
To synthesize NaHSO3, sulfuric acid reacts with sodium sulfite, creating a solution of NaHSO3. This method proves beneficial when requiring a more concentrated solution of NaHSO3.
Sodium Bisulfite Uses
NaHSO3 has a wide range of uses in various industries. Here are some of its common uses:
- Food industry – Used as a food preservative to prevent the growth of bacteria and prolong the shelf life of food products like canned fruits and vegetables, juices, and wine.
- Water treatment – Used as a reducing agent to remove excess chlorine from drinking water and wastewater treatment systems.
- Textile industry – Used as a bleaching agent to remove residual dyes from textiles.
- Photographic industry – Used as a developing agent in photographic processing.
- Oil drilling – Used as a corrosion inhibitor and in scavenging systems to remove oxygen and prevent corrosion in oil and gas drilling operations.
- Pharmaceuticals – Used as an antioxidant and as a reducing agent in the manufacture of some pharmaceutical products.
- Personal care – Used as a hair straightening agent and in the production of some personal care products like shampoos and conditioners.
- Other uses – Used in the production of paper and pulp, as a laboratory reagent, and as a metal ion chelating agent.
Questions:
Q: What is NaHSO3?
A: NaHSO3 is the chemical formula for sodium bisulfite, a salt that is used for a variety of purposes in different industries.
Q: What is the approximate pH of 0.015 M NaHSO3?
A: The approximate pH of 0.015 M NaHSO3 is around 7. This solution is neutral since it is not an acid or a base.
Q: Is NaHSO3 acidic or basic?
A: NaHSO3 is slightly acidic since it can donate a hydrogen ion in water to form HSO3- and H+ ions.
Q: What is the oxidation number of sulfur (S) in NaHSO3, one of the reagents used in this experiment?
A: The oxidation number of sulfur (S) in NaHSO3 is +4.
Q: What does NaHSO3 do?
A: NaHSO3 is used as a reducing agent and as a source of sulfur dioxide. It can also act as an antioxidant and preservative in food and pharmaceutical products.
Q: If you wish to prepare 1.00 kg of I2, what masses of NaIO3 and NaHSO3 are required?
A: The balanced chemical equation for the reaction between NaIO3 and NaHSO3 to form I2 is: 5NaIO3 + NaHSO3 + 3H2O → 3I2 + 5NaSO4 + 3H2SO4 Using stoichiometry, you would need 3.33 kg of NaIO3 and 1.00 kg of NaHSO3 to prepare 1.00 kg of I2.
Q: Why did we add sodium bisulfite at the end of the reaction?
A: NaHSO3 is added at the end of some chemical reactions to remove excess bromine, which can be harmful or interfere with subsequent steps in the process.
Q: What is sodium bisulfite?
A: NaHSO3 is a salt that is used for its reducing, antioxidant, and preservative properties in various industries, including food, pharmaceuticals, and water treatment.
Q: How does sodium bisulfite remove bromine?
A: NaHSO3 reacts with bromine to form sodium bromide and sulfur dioxide gas, effectively removing the excess bromine from a solution.
Q: What is menadione sodium bisulfite complex?
A: Menadione sodium bisulfite complex is a synthetic compound that is used as a source of vitamin K in some dietary supplements and animal feed products.
Q: What is sodium bisulfite used for?
A: NaHSO3 is used as a reducing agent, antioxidant, and preservative in various industries, including food, pharmaceuticals, water treatment, and oil drilling. It can also be used as a hair straightening agent and in photographic processing.