ABC of Safety in the Biological Sciences

 


 

NITRIC ACID (HNO3)

SYNONYMS
Aqua fortis.
GENERAL PRECAUTIONS
Use a fume hood.
Avoid skin and eye contact.
Avoid inhalation of the vapour.
Avoid ingestion.
Keep away from heat.
Keep away from organic materials.
Wash hands thoroughly after handling.
Do not dilute with tap water
CHARACTERISTICS
Colourless to yellow, fuming liquid with a choking odour.
HEALTH HAZARD DATA
Nitric acid is a highly corrosive substance and must be handled with great care. It will cause severe burns to any exposed areas. The vapour is a strong irritant and also corrosive. The vapour will corrode teeth. The recommended maximum level of exposure without self­contained breathing apparatus is 2 parts per million (5 mgm/m3) (National Health & Medical Research Council). Using tap water as a diluent may cause nitric acid to explode. Tap water contains many contaminants some of which may be incompatible with the acid. Use only de ionised or distilled water as a diluent.
TREATMENTS
Skin ­ immediately remove contaminated clothing and wash the affected area with soap or mild detergent and large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). Burns will require medical attention. Wash contaminated clothing before re­use.
Eyes ­ immediately wash the affected eye with large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). Seek medical attention.
Inhalation ­ remove from the area of exposure to fresh air. If breathing has ceased apply artificial respiration. Keep warm and allow to rest. Seek immediate medical attention.
Ingestion ­ wash out the mouth thoroughly with water and give water to drink. Do not induce vomiting. Seek immediate medical advice.
INCOMPATIBILITY
Heating produces toxic fumes of nitrogen oxides. Incompatible with oxidising agents, acids, alkalis, many organic materials (eg. wood, paper), brass, bronze, polythene and plasticised PVC. May be incompatible with ceratin tap waters.
STORAGE
Store in a cool, dry atmosphere away from direct sunlight, heat and incompatible substances.
HANDLING
Use a fume hood to minimise exposure to this substance. Wear protective clothing. A long sleeved laboratory coat or gown, rubber gloves, safety goggles and a face mask as a minimum standard.
DISPOSAL
WEAR:
Rubber gloves, laboratory coat and self contained breathing apparatus. have a body shield available.
SPILLS:
Cover the contaminated surface with sodium bicarbonate or soda ash-slaked lime mixture (50/50). Mix, and add water if necessary to form a slurry. scoop up the slurry and discharge to the sewer with a large excess of water.. wash the spill site with a soda ash solution.
PACKAGE LOTS:
Add slowly to a large volume of an agitated solution of soda ash and slaked lime until the solution is neutral. Discharge to the sewer with a large excess of water.
ENVIRONMENT:

 


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