VOLATILE ACIDS by Ion Chromatography: METHOD 7907, Issue 1, dated 20 May 2014 - Page 6 of 6
TABLE 1. General Information Acid MW HCl 36.46 HBr 80.91 HNO3 63.01
CAS Number 7647-01-0 10035-10-6 7697-37-2
RTECS Number MW4025000 MW3850000 QU5775000
TABLE 2. Occupational Exposure Limits Acid OSHA a HCl C 5 ppm, 7 mg/m3 HBr 8 hr TWAb 3 ppm 10 mg/m3 HNO3 8 hr TWAb 2 ppm 5 mg/m3 a b c d
NIOSH C 5 ppm, 7 mg/m3 Ca 3 ppm, 10 mg/m3 TWAc 2 ppm 5 mg/m3 STELd 4 ppm 10 mg/m3 a
Ceiling Limit Time-Weighted Average Up to 10 hr TWA in a 40 hr work week Short Term Exposure Limit
TABLE 3. Properties Acid Physical State HCl gas liquid
MP (°C) -114 --
BP (°C) -84.9 110
Vapor Pressure (VP) (38%) 28.3 kPa (azeotropic, 20.2%)
HBr
gas
-86.9
-66.8
2026.4 kPa
HNO3
liquid
-42
--
(68% Nitric) 101.3 kPa
NIOSH Manual of Analytical Methods (NMAM), Fifth Edition
