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Nitric acid

Synonyms & Trade Names
Aqua fortis, Engravers acid, Hydrogen nitrate, Red fuming nitric acid, RFNA, White fuming nitric acid (WFNA)
CAS No.
7697-37-2
RTECS No.
QU5775000
DOT ID & Guide
2031 157(other than red fuming)
2032 157(fuming)
Formula
HNO₃
Conversion
1 ppm = 2.58 mg/m3
IDLH
25 ppm
See: 7697372
Exposure Limits
NIOSH REL
TWA 2 ppm (5 mg/m3) ST 4 ppm (10 mg/m3)
OSHA PEL
TWA 2 ppm (5 mg/m3) See Appendix G
Measurement Methods
NIOSH 7903;
OSHA ID165SG
See: NMAM or OSHA Methods
Physical Description
Colorless, yellow, or red, fuming liquid with an acrid, suffocating odor. [Note: Often used in an aqueous solution. Fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide.]
Molecular Weight
63.0
Boiling Point
181°F
Freezing Point
-44°F
Solubility
Miscible
Vapor Pressure
48 mmHg
Ionization Potential
11.95 eV
Specific Gravity
(77°F): 1.50
Flash Point
NA
Upper Exposive Limit
NA
Lower Explosive Limit
NA
Noncombustible Liquid, but increases the flammability of combustible materials.
Incompatibilities & Reactivities
Combustible materials, metallic powders, hydrogen sulfide, carbides, alcohols [Note: Reacts with water to produce heat. Corrosive to metals.]
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, skin, mucous membrane; delayed pulmonary edema, pneumonitis, bronchitis; dental erosion
Target Organs
Eyes, skin, respiratory system, teeth
Personal Protection/Sanitation
(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet or contaminated
Change:No recommendation
Provide:Eyewash (pH<2.5), Quick drench (pH<2.5)
First Aid
(See procedures)
Eye:Irrigate immediately
Skin:Water flush immediately
Breathing:Respiratory support
Swallow:Medical attention immediately
Respirator Recommendations

NIOSH/OSHA

Up to 25 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*
(APF = 50) Any chemical cartridge respirator with a full facepiece and cartridge(s) providing protection against the compound of concern¿
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern¿
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern¿
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0183   MEDICAL TESTS: 0158

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