Registration Dossier
Registration Dossier
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EC number: 231-639-5 | CAS number: 7664-93-9
Endpoint summary
Administrative data
Description of key information
Additional information
The majority of the available data on the physical and chemical properties of sulphuric acid is taken from public domain reviews including the OECD SIDS (2001) and the 1998 review by the UK Pesticides Safety Directorate. The physical and chemical properties of sulphuric acid are well characterised due to the extensive industrial use and are summarised in the table below.
Sulphuric acid is a strong mineral acid that has a high affinity for (and is miscible with) water. It dissociates in water to form sulphate and hydrogen (hydronium) ions. The dissolution and dissociation of sulphuric acid in water is strongly exothermic and occurs with a vigorous reaction.
While pure (100%) sulphuric acid can be manufactured, this material loses some SO3 and the stability of the 98% grade acid and below is much greater. Sulphuric acid (95-98%) is the most common form and is referred to as concentrated sulphuric acid.
A number of the physical and chemical properties of sulphuric aicd are highly influenced by its purity (water content). Waivers are proposed (based on the nature of the substance and its reactivity with water) for granulometry, partition coefficient and surface tension.
Property |
Value |
Substance type |
Inorganic compound |
Appearance/physical state/colour |
Colourless to brown, viscous liquid. |
Melting/freezing point |
10.4 to 10.9°C (100% sulphuric acid) -1.11 to 3.0°C (98% sulphuric acid) -13.89 to -10°C (96% sulphuric acid) 7.56°C (83% sulphuric acid) |
Boiling point (at 1013 hPa) |
290°C (100% sulphuric acid) 310-335°C (98% sulphuric acid) 330°C (96% sulphuric acid) 360°C (77% sulphuric acid) |
Density at 20°C |
1.8144-1.8305 kg/L (90-100% sulphuric acid) |
Particle size distribution |
Not required for a liquid |
Vapour pressure |
130 Pa (97% sulphuric acid) |
Vapour pressure |
214 Pa (65% sulphuric acid) 6 Pa (90% sulphuric acid) |
Partition Coefficient |
Not relevant for ionisable substances |
Water solubility at 20°C |
Miscible |
Surface Tension at 25°C |
Not expected to be surface active |
Flash point |
Waiver |
Self ignition temperature |
Waiver |
Flammability |
Non-flammable |
Explosiveness |
Not expected to possess explosive properties. |
Oxidising properties |
Does not meet the criteria for classification as an oxidiser |
Stability in organic solvents and identity of relevant degradation products |
Not considered critical for an inorganic acid |
Dissociation constant |
pKa= 1.92 |
Viscosity |
A viscosity of 22.5 cP (0.0025 PaS; 22.5 mPaS) is reported for 95% sulphuric acid at 20 degrees Celsius. |
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