Phosphoric Acid 20% V/V - Descaler / Rust remover


SKU: RD11740

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Technical grade

Properties of Phosphoric Acid:

  • CAS No: 7664-38-2
  • EC No: 231-633-2
  • UN No. 1805
  • Formula: H3PO4
  • Appearance: Colourless liquid
  • Molar mass: 98.00 g/mol
  • Boiling point: 158 C
  • Health classification: Irritant

Phosphoric acid is classified as corrosive above 25% concentration. Between 10% and 25% it is classified as an irritant and below 10% it is not classified as harmful.


  • A rust remover
  • A descaler for removing scale from kettles, toilets etc.
  • Milk stone remover in dairy industry
  • Phosphoric acid is used as the electrolyte in phosphoric acid fuel cells.
  • Phosphoric acid is used as a cleaner by construction trades to remove mineral deposits, cementitious smears, and hard water stains.
  • Hot phosphoric acid is used in microfabrication to etch silicon nitride (Si3N4).
  • Phosphoric acid is used as a flux by hobbyists (such as model railroaders) as an aid to soldering.
  • Phosphoric acid is also used in hydroponics pH solutions to lower the pH of nutrient solutions. While other types of acids can be used, phosphorus is a nutrient used by plants, especially during flowering, making phosphoric acid particularly desirable. General Hydroponics pH Down liquid solution contains phosphoric acid in addition to citric acid and ammonium bisulfate with buffers to maintain a stable pH in the nutrient reservoir.
  • Phosphoric acid is used as an electrolyte in copper electropolishing for burr removal and circuit board planarization.
  • Phosphoric acid is also used for High Performance Liquid Chromatography.
  • Phosphoric acid can be used as an additive to stabilize acidic aqueous solutions within a wanted and specified pH range.


PLEASE NOTE: This product is not for human or animal consumption.