Benzoates (salts of benzoic acid) — properties & hazards overview
Volatility
Negligible (non-volatile salts)
Water solubility
High (alkali benzoates)
Acid/base
pKₐ(benzoic acid) ≈ 4.2
Typical form
Aerosol/mist or fines
Toxicity
irritant
Flammability
salts non-flammable
Chronic risk
sensitisation (rare)
Environmental
COD/BOD load
| Property | Value / Note |
|---|---|
| Chemical class | Salts of benzoic acid (e.g., sodium, potassium, ammonium benzoate) |
| Representative formula | M⁺ C₇H₅O₂⁻ (M = Na, K, NH₄) |
| Molar mass (examples) | Benzoate anion 121.1 g/mol; Na benzoate 144.1 g/mol; K benzoate 160.2 g/mol |
| Physical state (20 °C) | Crystalline solids; encountered as dissolved salts, mists or fines |
| Odour | Faint/none (salts); aromatic note if benzoic acid present |
| Water behaviour | Alkali salts highly soluble; acidification (pH <~5) forms benzoic acid → low solubility, precipitates |
| Typical uses | Food preservative (Na/K benzoate), corrosion inhibitor, intermediates |
*Values are indicative; always consult the latest SDS/standards for design and safety.