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What it is. This hydrochloric acid solution is a 0.1 N (0.1 M) volumetric standard, supplied in a 1 gallon size. It is a clear, colorless titrant for determining bases, alkalinity, and nitrogen in routine and regulated analysis.
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Molar equals normal. Hydrochloric acid releases one hydrogen ion per molecule, so its normality equals its molarity. A 0.1 N solution contains 0.1 mole of HCl per liter, about 3.646 g of hydrogen chloride (calculated), and each milliliter neutralizes 0.1 millimole of base, equal to 4.000 mg of sodium hydroxide.
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A strong acid in solution. HCl dissociates completely in water, so the hydrogen ion concentration matches the stated concentration. That complete dissociation gives sharp, predictable endpoints in acid-base titrations against strong and weak bases.
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Why 0.1 N is the workhorse strength. At 0.1 N, typical titrations of bases and alkaline samples use 10 to 50 mL of titrant, which keeps burette reading error small. It is the most common strength for back-titrations in nitrogen determinations and for titrating carbonate and hydroxide alkalinity.
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Kjeldahl and alkalinity work. In Kjeldahl nitrogen determination, ammonia distilled from a digested sample is trapped and titrated with standard acid, and 0.1 N HCl is one of the common titrants for this step. In alkalinity testing, the same acid titrates hydroxide, carbonate, and bicarbonate to defined pH endpoints.
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Size for daily use. The 1 gallon size gives one consistent lot for daily titrations, which reduces how often the solution must be restandardized and helps keep results comparable from day to day.
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Low hazard at working strength. Dilute 0.1 N hydrochloric acid is far less hazardous to handle than concentrated acid. It no longer fumes, though it can still irritate eyes and skin and corrode metals, so goggles and gloves remain standard.
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Standardization and accuracy. For the most accurate work, verify the concentration against a primary standard base such as sodium carbonate or tris(hydroxymethyl)aminomethane (THAM), and keep the container closed to prevent evaporation and contamination.
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Where it is used. Laboratories use 0.1 N HCl to titrate bases and alkaline samples, standardize sodium hydroxide solutions, back-titrate ammonia in Kjeldahl nitrogen methods, measure alkalinity, and adjust pH in sample preparation. The 1 gallon size supports QC labs that titrate every day.
Technical Specifications
| Chemical Name |
Hydrochloric acid, aqueous solution |
| CAS Numbers |
7647-01-0 (hydrogen chloride); 7732-18-5 (water) |
| EC Number (HCl) |
231-595-7 |
| Synonyms |
Hydrogen chloride solution, muriatic acid |
| Formula (active) |
HCl |
| Molecular Weight (active) |
36.46 g/mol |
| Concentration |
0.1 N (0.1 M) |
| HCl Content |
About 3.646 g/L (calculated) |
| Neutralizing Capacity |
1.00 mL = 0.100 mmol base, 4.000 mg NaOH (calculated) |
| Appearance |
Clear, colorless liquid |
| Physical State |
Liquid, aqueous solution |
| Strength Basis |
Volumetric standard; verify by standardization |
| Storage |
Room temperature, tightly closed |
| Package Size |
1 gallon |
Applications / Common Uses
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Acid-base titration: Titrates bases and alkaline samples.
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NaOH standardization: Cross-checks sodium hydroxide titrants.
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Kjeldahl nitrogen: Back-titrates distilled ammonia.
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Alkalinity testing: Determines carbonate and hydroxide alkalinity.
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pH adjustment: Lowers pH in sample preparation.
Storage, Handling & Shipping
Store tightly closed in a cool, well-ventilated corrosives cabinet, away from bases, oxidizers, metals, and cyanide or sulfide salts, which release toxic gases with acid. When diluting, always add acid slowly to water, never water to acid.
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Incompatible materials: Bases, oxidizers (including bleach and permanganate), reactive metals, cyanides, and sulfides.
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Exposure limit (hydrogen chloride): OSHA PEL and NIOSH REL: 5 ppm ceiling.
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Spill response: Ventilate, contain, and neutralize with sodium bicarbonate or an acid spill kit before cleanup.
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First aid: Skin or eyes: flush with water for at least 15 minutes and seek medical attention. Inhalation: move to fresh air.
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