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What it is. This sulfuric acid solution is a 50% (v/v) dilution: one volume of concentrated sulfuric acid made up to two volumes with water, supplied in a 1-gallon size. Many methods call for it as sulfuric acid (1+1).
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How strong it is. Comparable 50% (v/v) solutions have a specific gravity of about 1.49. Because concentrated acid is about 18 M, a 1+1 dilution is roughly 9 M (about 18 N, calculated), which is strong, dense, and highly corrosive.
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Why buy it pre-diluted. Mixing concentrated sulfuric acid with water releases a large amount of heat and can boil and spatter. A ready-made 50% solution removes the most hazardous preparation step and gives the same strength every time a method references it.
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Method reagent. Standard water, wastewater, and industrial methods often specify sulfuric acid (1+1) to acidify samples, prepare digests, and add acid to colorimetric and titrimetric reactions. Using a prepared solution keeps the reagent exactly as written.
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Strongly dehydrating. Even at 50% by volume, sulfuric acid strongly attracts water and chars sugars, paper, and other organic materials. Keep it away from organics and combustibles, and store it in a dedicated acid cabinet.
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Further dilution. When diluting further, add the 50% acid slowly to cold water with stirring. Dilution still releases significant heat, so use an ice bath for larger volumes and allow the solution to cool before adjusting volume.
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Handling at a glance. Wear chemical splash goggles, a face shield, acid-resistant gloves, and an apron, and keep an eyewash and safety shower nearby. Sulfuric acid burns deeply and quickly, so rinse any contact immediately for at least 15 minutes.
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Related products. For other strengths, see Lab Pro's Sulfuric Acid 10% (v/v) Solution, 1 Gallon and concentrated Sulfuric Acid 96%, ACS Grade, 500 mL.
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Where it is used. Fifty-percent sulfuric acid is used for sample acidification and digestion, COD and nutrient method reagents, colorimetric reactions, cleaning and etching, and preparing working-strength acid solutions in water, environmental, and industrial labs.
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) |
| Concentration |
50% (v/v), equivalent to 1+1 |
| Specific Gravity (comparable products) |
About 1.49 |
| Approximate Molarity |
About 9 M (about 18 N), calculated from 18 M concentrate |
| Appearance |
Clear, colorless liquid |
| Hazard Profile |
Causes severe skin burns and eye damage; corrosive to metals |
| DOT (comparable products) |
UN1830, Sulfuric acid, Class 8, PG II |
| Exposure Limit (mist) |
OSHA PEL and NIOSH REL: 1 mg/m³ TWA |
| Package Size |
1 gallon |
Applications / Common Uses
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Sample acidification: Acidifies water and wastewater samples.
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Digestion: Supports acid digestions in sample preparation.
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Method reagent: Supplies sulfuric acid (1+1) as written in methods.
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Colorimetric reactions: Provides acid for color development steps.
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Working dilutions: Prepares weaker sulfuric acid solutions.
Storage, Handling & Shipping
Caution: This sulfuric acid causes severe skin burns and eye damage, reacts violently with water, and is corrosive to metals. Always add acid slowly to water, never water to acid. Wear chemical splash goggles, a face shield, acid-resistant gloves, and an apron, and work in a fume hood.
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.
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