By A.P. Mentzer
Updated Mar 24, 2022
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Corrosive substances—particularly acids and bases—inflict significant damage on skin, eyes, mucous membranes, and respiratory passages. Their harmful effects depend on concentration, exposure duration, and the inherent strength of the chemical.
Acids and bases are corrosive. Tissue damage correlates with the chemical’s strength, concentration, and exposure time.
The pH scale quantifies hydrogen‑ion concentration in a solution, ranging from 0 (most acidic) to 14 (most alkaline). A pH below 7 indicates acidity; a pH above 7 denotes alkalinity. Strong acids readily release H⁺ ions, while strong bases liberate OH⁻ ions, driving complete dissociation.
Acids with a pH below 4, such as hydrochloric, nitric, sulfuric, and phosphoric acids, can cause immediate chemical burns. Although weak acids—acetate, citric, carbonic—are typically non‑corrosive at low concentrations, higher levels can become hazardous. Vapors from strong acids are water‑soluble and can damage ocular and respiratory tissues.
Bases exceeding a pH of 10—like sodium hydroxide, potassium hydroxide, and calcium hydroxide—can inflict severe burns. Unlike acid burns, alkaline injuries often progress silently because they feel slippery and may not provoke immediate pain. Exothermic reactions with water and lipid tissues can lead to deep, irreversible damage.
Typical skin manifestations include redness, pain, blistering, and peeling. In mucous membranes and airways, swelling, inflammation, chest pain, and breathing difficulty may occur. Eye exposure can cause watering, pain, corneal ulcers, and vision loss. Ingestion leads to internal irritation, vomiting, and diarrhea.
