Phosphoric acid
- White phosphoric acid
- Orthophosphoric acid
Phosphoric acid | |
| |
| Formula | H3PO4 |
| Structure | |
| Description | A clear colorless liquid or transparent crystalline solid. |
| Uses | Polymer gasoline catalyst, etchant (semiconductor manufacture), acidulant (soft drinks, prepared foods), aluminum brighteninganodizing agent, aluminumsteelmagnesiumzinc anticorrosion treatment reagent, microbial fermentation nutrient, refractories raw material. |
Registry Numbers. | |
| CAS | 7664-38-2 |
| EINECS | 231-633-2 |
| RTECS | TB6300000 |
| Std. Transport No. | 4930248 4930247 4930249 |
| EPA Pest. No. | 76001 |
| UN (DOT) | 1805 |
| Merck Index | 7500 |
| 7664-38-2 is listed on the TSCA. | |
Chemical and physical properties. | |
| Formula mass | 98 |
| Boiling point, °C | 150 |
| Vapor pressure, mmHg | 0.03 |
| Vapor density (air=1) | 3.4 |
| Specific gravity/density | 1.892 |
| Solubility in water | Miscible |
| Refractive index | 1.34203 |
Hazards and protection. | |
| Storage | May be stored in suitable stainless steel containers. (Hot acid attacks porcelain and graniteware). |
| Handling | Containers of this material may be hazardous when emptied. Since emptied containers retain product residues (vapor, liquid, and/or solid), all hazard precautions given in the data sheet must be observed. Addition to water releases heat which can result in violent boiling and spattering. Always add slowly and in small amounts. Never use hot water. Never add water to acids. Always add acids to water. |
| Protection | Wear appropriate protective gloves, clothing and goggles. |
| Respirators | Wear positive pressure self-contained breathing apparatus (SCBA). |
| Small spills or leaks | Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Neutralize spilled material with crushed limestone, soda ash, or lime. Apply water spray or mist to knock down vapors. Vapor knockdown water is corrosive or toxic and should be diked for containment. Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash or cement powder. Neutralize with agricultural lime (CaO), crushed limestone (CaCO3) or sodium bicarbonate (NaHCO3). Water spill: Neutralize with agricultural lime (CaO), crushed limestone (CaCO3), or sodium bicarbonate (NaHCO3). Adjust pH to neutral (pH=7). Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates. |
| Stability | Stable. |
| Incompatibilities | Reacts exothermically with bases May react with active metals, including such structural metals as aluminum and iron, to release hydrogen, a flammable gas Reacts with cyanide compounds to release gaseous hydrogen cyanide Reacts violently with sodium tetrahydroborate. |
| Hazardous Decomposition | Oxides of phosphorus are formed during thermal decomposition. Decomposition products: converted to pyrophosphoric acid (h4p2o7) when heated to 213 oC. |
| Other hazards | Hot acid attacks porcelain and graniteware. Very corrosive to ferrous metals and alloys. |
Fire related information. | ||||
| NFPA | Health | 2 |
 
 |
|
| Flammability | 0 | |||
| Reactivity | 0 | |||
| Special | - | |||
| Fire fighting | Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. | |||
| Fire potential | May heat combustibles to ignition point. | |||
| Hazards | Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. | |||
| Combustion products | Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. | |||
Health related information. | |
| Exposure limit(s) | OSHA PEL: TWA 1 mg/m3 NIOSH REL: TWA 1 mg/m3 ST 3 mg/m3 NIOSH IDLH: 1000 mg/m3 |
Exposure effects | |
| Coma and seizures have occurred. | |
| Ingestion | Irritation or burns of the oropharynx, esophagus, or gi tract may occur following ingestion. Nausea, vomiting, abdominal pain, hematemesis, bloody diarrhea, and perforation with severe burns may be noted. |
| Inhalation | Respiratory tract irritation and coughing may develop. Aspiration pneumonitis has occurred. |
| Skin | Dermal irritation or burns may develop. |
| Eyes | Eyes, nose, and throat irritation may occur. |
| First aid | |
| Ingestion | Seek medical assistance. |
| Inhalation | Move victim to fresh air. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. |
| Skin | Remove contaminated clothing and wash exposed area thoroughly with soap and water. A physician should examine the area if irritation or pain persists. |
| Eyes | Irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist, the patient should be seen in a health care facility. |
Shipping information. | ||
| DOT (UN) Transportation Information |
 | |
| UN number | 1805 | |
| Response guide | 154 | |
| Hazard class | 8 | |