Chemical laboratory

Phosphoric Acid

Versatile Inorganic Acid for Industrial Applications

  • CAS 7664-38-2
  • Formula H₃PO₄
  • Flash Pt N/A °C
  • Density 1.834 g/cm³
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Physical & Chemical Properties

Property Value Unit
Boiling point 158 °C °C
Flash point N/A °C
Density 1.834 g/cm³ g/cm³
Solubility Miscible with water -
Ph < 1 (concentrated) -
Molecular weight 98.00 g/mol g/mol
Melting point 42.35°C °C
Vapor pressure N/A mmHg
Autoignition temp N/A -
Appearance Clear, colorless, viscous liquid -
Odor Odorless -
Vapor density 3.4 (air = 1) g/cm³

Overview

Phosphoric acid (H₃PO₄) is a clear, colorless, viscous inorganic acid with exceptional versatility across multiple industries. With a molecular weight of 98.00 g/mol and complete water miscibility, this odorless compound serves as a fundamental building block in fertilizer production, metal treatment, food processing, and numerous chemical manufacturing processes. Its strong acidic properties (pH < 1 when concentrated) make it an effective agent for pH adjustment, rust removal, and surface preparation applications.

Key Applications

  • Fertilizer Production: Essential component in manufacturing phosphate fertilizers, providing crucial phosphorus nutrients for agricultural applications
  • Metal Surface Treatment: Highly effective for rust removal, metal cleaning, and surface preparation before coating or plating operations
  • Food Industry: FDA-approved food additive used for pH control, flavor enhancement, and preservation in beverages and processed foods
  • Chemical Manufacturing: Critical intermediate in producing phosphate salts, detergents, and various specialty chemicals

Safety & Handling

Phosphoric acid is non-flammable with no flash point or autoignition temperature, making it safer to handle than many industrial acids. However, proper safety protocols are essential due to its corrosive nature. Always wear appropriate personal protective equipment including chemical-resistant gloves, safety goggles, and protective clothing. Ensure adequate ventilation when handling concentrated solutions to prevent vapor inhalation. The vapor density of 3.4 (air = 1) means vapors will settle in low areas, requiring proper workspace ventilation design.

Storage & Shelf Life

Store phosphoric acid in corrosion-resistant containers such as stainless steel, fiberglass, or appropriate plastic materials. Avoid contact with metals, strong bases, and organic materials that may cause unwanted reactions. Maintain storage temperatures below the boiling point of 158°C and above the melting point of 42.35°C to prevent phase changes. With proper storage conditions, phosphoric acid maintains its chemical properties indefinitely, though container integrity should be regularly monitored.

Why Alliance Chemical

Alliance Chemical provides reliable same-day shipping of high-quality Phosphoric Acid from our Taylor, Texas facility. We offer flexible shipping options including UPS, LTL, and FTL services to meet your delivery requirements. Every shipment includes comprehensive Safety Data Sheets (SDS) and Certificate of Analysis (COA) documentation, ensuring you receive consistent, specification-grade material for your critical applications.

Shipping & Availability

Parcel Shipping

UPS Ground supports pints, quarts, and most 1-gallon packages nationwide.

LTL Freight

5-gallon pails, drums, and totes move via LTL carriers such as ABF Freight, SEFL, Saia, and XPO.

Full Truckload

FTL available for palletized bulk orders. Competitive freight rates.

Local Pickup

Same-day pickup at our Taylor, TX warehouse for Texas customers.

SDS, COA, and TDS available for every product • Same-day shipping on orders by Mon-Thu 1 PM CT / Fri 12 PM CT

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Frequently Asked Questions

What is phosphoric acid (H3PO4) and what is it used for?
Phosphoric acid (CAS 7664-38-2, formula H3PO4) is a colorless, non-volatile inorganic acid commonly supplied as an 85% aqueous solution. It is used industrially as a raw material for phosphate salts and fertilizers, metal treatment (rust removal, pickling, passivation), pH control, detergent manufacture and as a laboratory reagent.
How should 85% phosphoric acid be stored and what is its shelf life?
Store in a cool, dry, well‑ventilated area in tightly closed corrosion‑resistant containers away from bases, strong oxidizers and reactive metals; keep out of direct sunlight and heat. The product is chemically stable with a typical shelf life of 12–24 months if stored under recommended conditions; consult the supplier for extended storage guidance.
What safety precautions and personal protective equipment (PPE) are required when handling phosphoric acid?
Handle as a corrosive substance: wear chemical splash goggles, face shield, acid‑resistant gloves and apron, and use local exhaust or respiratory protection if mists are possible. Have an eyewash and safety shower available, avoid skin and eye contact, and follow the product SDS for first aid and emergency procedures.
How do different concentrations of phosphoric acid affect its use and hazards?
Higher concentrations (e.g., 85%) are stronger, more corrosive and suitable for industrial applications like metal treatment, while dilute solutions are used for laboratory work and pH adjustment; concentration affects freezing/boiling points, corrosivity and handling precautions. Always select the concentration appropriate to the application and follow dilution procedures from the SDS.
What documentation is available for phosphoric acid before purchase?
Suppliers typically provide a Safety Data Sheet (SDS), Certificate of Analysis (COA), Technical Data Sheet (TDS) and packing list; regulatory documents such as REACH registration or transport declarations are available on request. Review the SDS for hazard, storage, handling and disposal information before use.
How is phosphoric acid shipped and what packaging options are common?
Phosphoric acid is classified as a corrosive liquid and shipped under applicable hazardous materials regulations (e.g., IMDG, IATA, 49 CFR) with appropriate labeling. Common packaging includes plastic drums (25–200 L), IBCs (~1,000 L) and bulk tankers; specific packaging depends on order size and transport rules.
Which materials are compatible or incompatible with phosphoric acid?
Compatible materials include HDPE, polypropylene, PTFE, glass and some stainless steels (e.g., 316) under normal conditions; avoid aluminum, zinc, brass and other active metals that corrode and may generate hydrogen. Compatibility depends on concentration, temperature and exposure time, so verify with supplier or perform compatibility testing for critical applications.
What are the typical technical specifications for 85% phosphoric acid?
Typical specs for an 85% grade include assay (H3PO4) ≥85% w/w, appearance: colorless to slightly yellow viscous liquid, molecular weight ~98.00 g/mol, and density around 1.68–1.70 g·mL−1 at 20°C. Additional specs such as heavy metals, chloride content and water content are provided on the COA or TDS from the supplier.
Which industries and applications commonly use phosphoric acid?
Common industries include fertilizer and phosphate chemical production, metal surface treatment (pickling, descaling, passivation), detergent and rust‑removal manufacturing, electronics cleaning and laboratory/reagent use. Applications vary by grade and concentration—from industrial processing to analytical reagent tasks.
How can I purchase 85% phosphoric acid and what affects availability and lead time?
Phosphoric acid is sold by chemical distributors and manufacturers in quantities from small laboratory bottles to bulk tanker loads; typical order channels include direct supplier sales, distributors and online catalogs. Availability and lead time depend on order size, regional regulations, transportation constraints and current market demand—contact suppliers for quotes, minimum order quantities and delivery schedules.

Documentation & Downloads

Safety Data Sheet
SDS / MSDS
Request COA
Certificate of Analysis
Technical Data Sheet (TDS)
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