How powerful is the acid in a car battery in terms of its ability to dissolve metal?
The sulfuric acid in a car battery is corrosive enough to dissolve a metal key in just a few hours.
Car batteries contain a highly corrosive sulfuric acid solution that stores and conducts electricity. When a metal key is submerged in this acid, a rapid chemical reaction begins that breaks down the metal's structure. The acid triggers oxidation, eating through the metal layer by layer until it completely dissolves into the liquid.
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Standard lead-acid car batteries, first invented by Gaston Planté in 1859, use an electrolyte solution of approximately 35% sulfuric acid and 65% water. This concentration creates a pH level near zero, making it extremely corrosive to organic tissue and most metals. When a metal key is submerged in this solution, a redox reaction occurs in which sulfuric acid acts as an oxidizing agent.The acid reacts with the metal to produce hydrogen gas and a metal sulfate salt. For instance, if the key contains iron, the reaction generates ferrous sulfate and hydrogen bubbles. This process is highly exothermic, releasing heat that accelerates corrosion. Over 8 to 12 hours, the metal's structural integrity breaks down as its atoms are stripped away and dispersed in the solution.The Occupational Safety and Health Administration (OSHA) classifies sulfuric acid as a Category 1 skin corrosive. Even brief contact causes third-degree chemical burns and permanent eye damage. Modern automotive batteries are sealed to prevent leaks, but older or damaged units risk acid spills that can destroy clothing and etch concrete surfaces almost instantly.
Verified Fact
FP-0003867 · Feb 18, 2026