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What it is. This sulfuric acid is a dilute aqueous solution specified by specific gravity (1.24), supplied in a case of four gallons. Solutions defined by specific gravity are typically used as battery electrolyte and in processes where a hydrometer controls acid strength.
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What specific gravity 1.24 means. Specific gravity compares the solution's density with water. Battery acid in the range of about 29 to 32% sulfuric acid has a density of about 1.25 to 1.28, so a 1.24 solution sits at the lower end of that electrolyte range (comparison from published concentration tables).
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Why specify by specific gravity. You can measure specific gravity quickly with a hydrometer in the field or shop, without titration. That makes it the practical way to specify, check, and adjust battery electrolyte and process acid strength.
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Battery electrolyte. In lead-acid batteries, electrolyte specific gravity rises as the battery charges and falls as it discharges. Use electrolyte supplied at a defined specific gravity to fill and adjust cells according to the battery manufacturer's specifications.
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Other uses. Specific-gravity-controlled sulfuric acid is also used in plating and anodizing baths, pH adjustment, and processes that rely on hydrometer checks rather than laboratory titration.
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Case of four. The four-gallon case suits battery maintenance programs, shops, and process lines that use electrolyte regularly, keeping stock in manageable one-gallon units.
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Checking strength. Measure specific gravity with a calibrated hydrometer at the temperature stated by the battery or process specification, applying temperature correction where required, since specific gravity changes with temperature.
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Temperature correction. Specific gravity decreases as electrolyte warms. Battery manufacturers publish correction factors, typically adding a small amount to the reading for each degree above the reference temperature and subtracting it for each degree below.
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Mixing and topping up. When adjusting battery cells, follow the manufacturer's instructions on whether to add electrolyte or water. In most maintenance, only water is added to replace losses, and electrolyte is used when acid has been spilled, or cells are being filled.
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Handling at a glance. Even dilute sulfuric acid can cause burns and corrode metals. Wear chemical splash goggles, acid-resistant gloves, and an apron, and keep baking soda or an acid spill kit nearby when filling batteries.
Technical Specifications
| Chemical Name |
Sulfuric acid, aqueous solution |
| CAS Numbers |
7664-93-9 (sulfuric acid); 7732-18-5 (water) |
| EC Number (H2SO4) |
231-639-5 |
| Synonyms |
Oil of vitriol (concentrated), battery acid (dilute), H2SO4 solution |
| Formula (active) |
H2SO4 |
| Molecular Weight (active) |
98.08 g/mol |
| Equivalent Weight |
49.04 (diprotic; normal = 2 x molar) |
| Specification |
Specific gravity 1.24 |
| Approximate Concentration |
Slightly below the battery acid range of about 29 to 32% (w/w); confirm on SDS |
| Battery Acid Reference Range |
About 29 to 32% H2SO4, density 1.25 to 1.28 |
| Measurement |
Hydrometer (apply temperature correction) |
| Appearance |
Clear, colorless liquid |
| Hazard Profile |
Causes skin and eye burns; corrosive to metals |
| DOT (comparable dilute sulfuric acid) |
UN2796, Sulfuric acid (or Battery fluid, acid), Class 8, PG II; confirm on SDS |
| Exposure Limit (mist) |
OSHA PEL and NIOSH REL: 1 mg/m³ TWA |
| Package Size |
Case of 4 gallons |
Applications / Common Uses
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Battery electrolyte: Fills and adjusts lead-acid battery cells.
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Battery maintenance: Supports electrolyte top-up programs.
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Plating and anodizing: Supplies controlled-strength acid for baths.
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pH adjustment: Acidifies process water.
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Hydrometer-controlled processes: Provides acid specified by density.
Storage, Handling & Shipping
Store tightly closed in a corrosives cabinet away from bases, reactive metals, organic materials, and water-reactive substances. When diluting, always add acid slowly to water, never water to acid, since dilution releases heat.
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Incompatible materials: Bases, reactive metals (release hydrogen), organic materials, oxidizers and reducers, and cyanides or sulfides.
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Exposure limit (sulfuric acid mist): OSHA PEL and NIOSH REL: 1 mg/m³ TWA.
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Spill response: Contain and neutralize with sodium bicarbonate or an acid spill kit, then rinse with water.
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First aid: Skin or eyes: flush with water for at least 15 minutes and seek medical attention.
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GHS signal word: Danger or Warning depending on concentration.
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DOT / shipping: UN2796, Sulfuric acid, Class 8; the Lab Pro SDS.
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