Phosphoric Acid
Uses
Removal of Rust:
One of the most common phosphoric acid uses is to remove rust from surfaces of metals. Phosphoric acid can be used as a rust converter with the help of direct application to rusted iron, or steel tools and other rusted surfaces.
Use in Processed Food:
Phosphoric acid is used as an additive to acidify foods and beverages like various colas. This use has managed to stir up a controversy regarding the health effects that this may have on the human body. It provides a tangy or a sour taste and being a mass produced chemical, it is available in large quantities easily.

Medical Uses:
One of the most important phosphoric acid uses is in medicine and dentistry. Phosphoric acid is used as an ingredient in over-the-counter anti-nausea medications which also happen to contain high levels of sugar, that is, glucose and fructose.
Other Phosphoric Acid Uses:
Phosphoric acid is used as the electrolyte in phosphoric acid fuel cells. Phosphoric acid is also used as a cleaner by construction trades so as to remove mineral deposits, cementinous smears and hard water stains. Hot phosphoric acid is used in micro-fabrication to etch silicon nitride.