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What it is. Ammonium chloride (NH4Cl), also known as sal ammoniac, is a white, free-flowing crystalline salt supplied in a 500 g size. This ACS reagent-grade material meets American Chemical Society specifications, with a minimum assay of 99.5% and defined limits for calcium, iron, heavy metals, sulfate, phosphate, insoluble matter, and residue after ignition.
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Why ACS grade matters. Ammonium chloride is a building block for analytical buffers, and trace calcium, magnesium, iron, or heavy metals carried in by the salt shift titration endpoints and raise blanks. ACS limits keep those impurities low and consistent from lot to lot, which supports reproducible complexometric, gravimetric, and qualitative results.
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Solubility and dissolving behavior. Ammonium chloride is highly soluble, about 372 g per liter of water at 20 °C, and dissolves with a noticeable temperature drop because the process absorbs heat. In temperature-sensitive procedures, return concentrated solutions to room temperature before pH adjustment or final dilution.
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Acidity in solution. The ammonium ion is a weak acid, so ammonium chloride solutions are mildly acidic: a 5% solution measures pH 4.5 to 5.5. Paired with ammonia, the ammonium/ammonia system has a pKa near 9.25, so mixtures of ammonium chloride and ammonium hydroxide make dependable alkaline buffers.
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The pH 10 ammonia buffer for hardness testing. Its best-known lab role is the ammonia-ammonium chloride buffer used in EDTA titrations of calcium and magnesium for total water hardness. Combined with Lab Pro's Ammonium Hydroxide 28 to 30% Solution, ACS Grade, it maintains a pH near 10, where Eriochrome Black T Indicator gives a sharp wine-red-to-blue endpoint with EDTA Titrant 0.1 N / 0.05 M.
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Behavior on heating. Ammonium chloride does not melt. Near 338 °C it sublimes, dissociating into ammonia and hydrogen chloride gases that recombine as white fumes on cooler surfaces. That behavior underlies its use in fluxes, where hot vapors help strip oxide films from metal, and it also explains why the salt should be heated only under ventilation.
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Uses in biology and microbiology. Ammonium chloride supplies nitrogen in defined microbial culture media and is the active component of ammonium chloride lysis buffers that selectively lyse red blood cells while leaving white blood cells intact for flow cytometry and cell isolation.
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Industrial and electrochemical uses. Beyond the lab, ammonium chloride is used in soldering, tinning, and galvanizing fluxes, as an electrolyte in zinc-carbon dry cells, and as a supporting electrolyte in electrochemistry. In qualitative analysis schemes, it controls pH and supplies common ions for selective precipitation.
Technical Specifications
| Chemical Name |
Ammonium chloride |
| CAS Number |
12125-02-9 |
| EC Number |
235-186-4 |
| PubChem CID |
25517 |
| Synonyms |
Sal ammoniac, salmiac, ammonium muriate |
| Formula |
NH4Cl |
| Molecular Weight |
53.49 g/mol |
| Grade |
ACS reagent |
| Assay |
99.5% min |
| pH (5% solution, 25 °C) |
4.5 to 5.5 |
| Insoluble Matter |
0.005% max |
| Residue after Ignition |
0.01% max |
| Heavy Metals (as Pb) |
0.0005% max |
| Iron (Fe) |
0.0002% max |
| Sulfate (SO4) |
0.002% max |
| Phosphate (PO4) |
0.0002% max |
| Appearance |
White crystalline solid |
| Water Solubility |
372 g/L at 20 °C |
| Sublimation Point |
338 °C (decomposes) |
| Calcium (Ca) |
0.001% max |
| Density |
1.53 g/cm3 |
| Oral LD50 (rat) |
1,410 mg/kg |
| Package Size |
500 g |
Applications / Common Uses
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EDTA titration buffer: Forms the pH 10 ammonia buffer used in water hardness testing with Eriochrome Black T.
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Electrolyte preparation: Supplies a conductive, non-interfering salt for electrochemistry and battery research.
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Microbiology and cell work: Serves as a nitrogen source in media and as the active agent in red blood cell lysis buffers.
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Metal finishing: Used in soldering, tinning, and galvanizing fluxes to clean oxide films from metal surfaces.
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Qualitative and gravimetric analysis: Controls pH and supplies common ions in classic precipitation and separation schemes.
Storage, Handling & Shipping
Store ammonium chloride in a tightly closed container in a cool, dry, ventilated area. The crystals can absorb moisture and cake, so close it promptly after weighing. Keep it away from strong bases (which release ammonia gas) and from strong oxidizers and nitrates. Avoid creating dust when weighing, and never heat the solid in a closed space, since it releases ammonia and hydrogen chloride fumes.
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Incompatible materials: Strong bases, strong oxidizers, nitrates, and potassium chlorate.
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Personal protection: Safety glasses, nitrile gloves, and dust control when weighing large amounts.
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Spill response: Sweep up without raising dust and place in a closed container; rinse residue with water.
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First aid: Eyes: rinse with water for several minutes. Ingestion: rinse mouth and seek medical advice.
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GHS signal word: Warning. Harmful if swallowed; causes serious eye irritation.
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