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What it is. This sulfuric acid is the concentrated ACS reagent grade, nominally 96% and meeting the ACS assay range of 95.0 to 98.0% H2SO4, supplied in a 500 mL size. It is a clear, colorless, oily, extremely corrosive liquid for analysis, digestion, synthesis, and preparing dilute acids.
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What ACS grade guarantees. ACS reagent sulfuric acid limits color to 10 APHA, residue after ignition to 5 ppm, chloride to 0.2 ppm, nitrate to 0.5 ppm, ammonium and permanganate-reducing substances to 2 ppm each, heavy metals to 1 ppm, iron to 0.2 ppm, arsenic to 0.01 ppm, and mercury to 5 ppb.
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How concentrated it is. With a density of about 1.84 g/cm³, concentrated sulfuric acid contains roughly 1,770 g of H2SO4 per liter, about 18 M or 36 N (calculated). It boils between 290 and 335 °C, depending on concentration.
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Powerful dehydrating agent. Concentrated sulfuric acid removes water from almost anything, charring sugars, paper, and skin. It serves as a drying agent for gases, a dehydrating reagent in organic synthesis, and a catalyst for esterification and nitration.
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Kjeldahl and COD digestion. Concentrated sulfuric acid is the digestion acid in Kjeldahl nitrogen analysis, where it converts organic nitrogen to ammonium sulfate, and in chemical oxygen demand (COD) methods with dichromate. ACS purity keeps blanks low in both.
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Preparing dilute acids. Concentrated acid is the starting point for volumetric and working solutions. About 28 mL diluted to 1 L gives roughly 1 N (calculated). Always add acid slowly to water, cool, and standardize. Ready-made strengths include Lab Pro's Sulfuric Acid 1.0 N Solution (1 L, 1 Gallon).
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Violent reaction with water. Adding water to concentrated sulfuric acid can boil the water instantly and spray acid. Add acid to water slowly with stirring and cooling, and never pour water into the acid.
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Handling at a glance. Work in a fume hood with chemical splash goggles, a face shield, acid-resistant gloves, and an apron. Store it on secondary containment in a corrosives cabinet, away from water-reactive substances, bases, metals, and organic materials.
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Absorbs moisture. Concentrated sulfuric acid is strongly hygroscopic and absorbs water from the air, slowly diluting itself. Keep containers tightly closed to preserve the ACS assay.
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) |
| Grade |
ACS reagent |
| Assay |
95.0 to 98.0% H2SO4 (nominal 96%) |
| Density |
About 1.84 g/cm³ (20 °C) |
| Approximate Molarity |
About 18 M (about 36 N), calculated |
| Boiling Point |
About 290 to 335 °C |
| Color (APHA) |
10 max |
| Residue after Ignition |
5 ppm max |
| Chloride (Cl) |
0.2 ppm max |
| Nitrate (NO3) |
0.5 ppm max |
| Ammonium (NH4) |
2 ppm max |
| Substances Reducing Permanganate (as SO2) |
2 ppm max |
| Heavy Metals (as Pb) |
1 ppm max |
| Iron (Fe) |
0.2 ppm max |
| Arsenic (As) |
0.01 ppm max |
| Mercury (Hg) |
5 ppb max |
| Hazard Profile |
Causes severe skin burns and eye damage; reacts violently with water |
| DOT |
UN1830, Sulfuric acid, Class 8, PG II |
| Exposure Limit (mist) |
OSHA PEL and NIOSH REL: 1 mg/m³ TWA |
| Package Size |
500 mL |
Applications / Common Uses
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Kjeldahl digestion: Converts organic nitrogen to ammonium sulfate.
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COD analysis: Supplies digestion acid for dichromate methods.
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Organic synthesis: Catalyzes esterification and nitration; dehydrates.
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Dilute acid preparation: Prepares volumetric and working sulfuric acid.
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Gas drying: Removes water vapor from gases.
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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