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EC number: 247-852-1 | CAS number: 26628-22-8
Henry's Law constant
Administrative data
Link to relevant study record(s)
- Endpoint:
- Henry's law constant
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Reason / purpose for cross-reference:
- reference to same study
- Qualifier:
- no guideline required
- GLP compliance:
- not specified
- H:
- >= 12 - <= 12.4 other: M atm-1
- Temp.:
- 25 °C
- Executive summary:
Based on three differend studies, the Henry's law constant was estimated to be 10 - 12.4 M/atm, with ionic strengh values of µ=0.02 - 11M.
- Endpoint:
- Henry's law constant
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- H:
- 10.132 Pa m³/mol
- Temp.:
- 30 °C
- Executive summary:
The volatility of hydrazoic acid (the protonated form of the azide anion) in acidified solution was reported to be 76 mm Hg /M, which is equal to 10.132 Pa/m^3/mol.
Referenceopen allclose all
The Henry's law constant, KH,in dilute aqueous solution was recently determined to be
KH= [HN3]/PHN3= 12.0 M atm-1(25 °C; µ = 0.02 M;DH = -31 ± 1 kJ mol-1)
Here, µ. =ionic strength.
This is in good agreement with two earlier studies conducted at higher ionic strengths. D'Orazio and Wood [J Phys Chem 1963, 67: 1435-8] reported KH = 12.2-12.4 M atm-1,μ= 0.10-1.65; while Templeton and King [J Am Chem Soc 1971, 93(26): 7160-6] reported KH = 12.1, µ=0.1 -11 M.
Volatility of hydrazoic acid from acidified solutions of sodium azide.
Description of key information
Betterton (2003) report a Henry's law constant between 10 - 12.4 M/atm. Weiss (1996) state a volatility of hydrazoic acid (the protonated form of the azide anion) in acidified solution of 76 mm Hg /M, which is equal to 10.132 Pa/m^3/mol.
Key value for chemical safety assessment
- Henry's law constant (H) (in Pa m³/mol):
- 10.132
- at the temperature of:
- 20 °C
Additional information
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