Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 231-901-9 | CAS number: 7778-39-4
Vapour pressure
Administrative data
Link to relevant study record(s)
Description of key information
Using a weight of evidence, the vapour pressure of arsenic acid was considered to be 18.45 hPa at 25 °C.
Key value for chemical safety assessment
- Vapour pressure:
- 18.45 hPa
- at the temperature of:
- 25 °C
Additional information
Two secondary bibliographic sources provide vapour pressure (VP) values for arsenic acid. As the primary reference is not traceable, both references are quoted by reliability score of 4 (not assignable). The available values are reported below:
(1) VP = 55 mbar at 50°C and VP = 110 mbar at 65°C
(2) VP = 12.58 hPa at 15°C
The vapour pressure may vary greatly according temperature. For the purpose of the chemical safety assessment, VP values at 25°C are predicted using the equation recommended in EUSES Software version 2.1: VPtempx = VPtemptest x e{ (H0_VP/R) x (1/Temptest – 1/Tempx) }
Where:
Tempx: temperature of 25°C (equal to 298.15 K)
Temptest: temperature of the measured physico-chemical data (15°C = 288.15 K; 50°C = 323.15 K)
H0_VP: enthalpy of vaporisation (value: 5.104 J.mol-1)
R: Gas constant (value: 8.314 Pa.m3.mol-1.K-1)
Values of extrapolated vapour pressure:
(1) Input 55 mbar at 50°C, Output: 11.5 hPa at 25°C
(2) Input 12.58 hPa at 15°C, Output: 25.4 hPa at 25°C
Both values are in the same order of magnitude. Using a weight of evidence, the arithmetic mean of the two values is proposed as key value for the chemical safety assessment: VP25°C = 18.45 hPa
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
