Reactivity and Incompatibility

Hydrochloric acid and hydrogen chloride react violently with many metals, with the generation of highly flammable hydrogen gas, which may explode. Reaction with oxidizers such as permanganates, chlorates, chlorites, and hypochlorites may produce chlorine or bromine.

Storage and Handling

Hydrochloric acid should be handled in the laboratory using the "basic prudent practices" described in Chapter 5.C. Splash goggles and rubber gloves should be worn when handling this acid, and containers of HCl should be stored in a well-ventilated location separated from incompatible metals. Water should never be added to HCl because splattering may result; always add acid to water. Containers of hydrochloric acid should be stored in secondary plastic trays to avoid corrosion of metal storage shelves due to drips or spills.


Hydrogen chloride gas should be handled in the laboratory using the "basic prudent practices" described in Chapter 5.C, supplemented by the procedures described in Chapter 5.H for the handling of compressed gases. Cylinders of hydrogen chloride should be stored in cool, dry locations separated from alkali metals and other incompatible substances.


In the event of skin contact, remove contaminated clothing and immediately wash with flowing water for at least 15 min. In case of eye contact, immediately wash with copious amounts of water for at least 15 min while holding the eyelids open. Seek medical attention. In case of ingestion, do not induce vomiting. Give large amounts of water or milk if available and transport to medical facility. In case of inhalation, remove to fresh air and seek medical attention.


Carefully neutralize spills of hydrochloric acid with a suitable agent such as powdered sodium bicarbonate, further dilute with absorbent material, place in an appropriate container, and dispose of properly. Dilution with water before applying the solid adsorbent may be an effective means of reducing exposure to hydrogen chloride vapor. Respiratory protection may be necessary in the event of a large spill or release in a confined area.


Leaks of HCl gas are evident from the formation of dense white fumes on contact with the atmosphere. Small leaks can be detected by holding an open container of concentrated ammonium hydroxide near the site of the suspected leak; dense white fumes confirm that a leak is present. In case of accidental release of hydrogen chloride gas, such as from a leaking cylinder or associated apparatus, evacuate the area and eliminate the source of the leak if this can be done safely. Remove cylinder to a fume hood or remote area if it cannot be shut off. Full respiratory protection and protective clothing may be required to deal with a hydrogen chloride release.


In many localities, hydrochloric acid or the residue from a spill may be disposed of down the drain after appropriate dilution and neutralization. Otherwise, hydrochloric acid and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines. Excess hydrogen chloride in cylinders should be returned to the manufacturer. For more information on disposal procedures, see Chapter 7 of this volume.

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