Phosphoric Acid

Synonyms: Ortho phosphoric acid

Phosphoric Acid CAS No.: 7664-38-2

Molecular Weight: 98.00 Chemical Formula: H3PO4

Composition/Information on Ingredients

Physical and Chemical Properties

Appearance: Clear, colorless syrupy liquid.

Odor: Odorless.

Solubility: Miscible in all proportions in water.

Specific Gravity: 1.69 @ 25C

pH: 1.5 (0.1 N aqueous solution)

% Volatiles by volume @ 21C (70F): 100

Boiling Point: 158C (316F)

Melting Point: 21C (70F)

Freezing Point: 21C (70F)

Vapor Density (Air=1): 3.4

Vapor Pressure (mm Hg): 0.03 @ 20C (68F)

Handling and Storage

Keep in a tightly closed container. Protect from physical damage. Store in a cool, dry, ventilated area away from sources of heat, moisture, incompatibilities, and direct sunlight. Corrosive to mild steel. Store in rubber lined or 316 stainless steel designed for phosphoric acid. Do not wash out container and use it for other purposes. When diluting, the acid should always be added slowly to water and in small amounts. Never use hot water and never add water to the acid. Water added to acid can cause uncontrolled boiling and splashing. Protect from freezing. Containers of this material may be hazardous when empty since they retain product residues (vapors, liquid); observe all warnings and precautions listed for the product.

Stability and Reactivity

Stability: Stable under ordinary conditions of use and storage. The substance can supercool without crystallizing.

Hazardous Decomposition Products: Phosphorus oxides may form when heated to decomposition.

Hazardous Polymerization: Will not occur.

Incompatibilities: Liberates explosive hydrogen gas when reacting with chlorides and stainless steel. Can react violently with sodium tetrahydroborate. Exothermic reactions with aldehydes, amines, amides, alcohols and glycols, azo-compounds, carbamates, esters, caustics, phenols and cresols, ketones, organophosphates, epoxides, explosives, combustible materials, unsaturated halides, and organic peroxides. phosphoric acid forms flammable gases with sulfides, mercaptans, cyanides and aldehydes. It also forms toxic fumes with cyanides, sulfides, fluorides, organic peroxides, and halogenated organics. Mixtures with nitromethane are explosive.

Conditions to Avoid: Incompatible.