Phosphoric acid
Molar mass: 97.99 g/mol · Class: Weak triprotic acid
Elements: hydrogen, phosphorus, oxygen
Structure
The molecule has a central phosphorus bonded tetrahedrally to four oxygens, three carrying hydrogens. It can lose up to three protons stepwise, making it triprotic.
Properties
Weak triprotic acid
Thick, syrupy liquid in concentrated form
Gives cola its characteristic tang
Converts to phosphates used in fertilizers
Applications
Fertilizer production (the largest use)
Acidulant in soft drinks
Rust remover and metal treatment
Detergents and food additives
Concentrated acid burns skin and eyes: wear goggles and gloves. Food-grade dilute use is regulated; do not drink concentrated forms. Excess phosphate in wastewater harms waterways.
Data source: IUPAC standard atomic weights 2021; molar mass computed from H3PO4