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What it is. This mercuric nitrate solution is a 0.01 N volumetric titrant, supplied in a 1 L size, used to determine chloride in water and wastewater by mercurimetric titration. It is a clear, colorless, acidified aqueous solution.
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How the titration works. Mercuric ions combine with chloride to form soluble but only slightly dissociated mercuric chloride. Once all chloride has reacted, excess mercuric ion forms a blue-violet complex with diphenylcarbazone indicator, marking the endpoint.
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Why the endpoint is easier to see. Compared with the silver nitrate method, the mercuric nitrate endpoint is sharper and easier to detect, and the method suits lower chloride levels. Standard Methods 4500-Cl⁻ C specifies a pH range of 2.3 to 2.8, with xylenol orange or bromophenol blue as the indicator showing the correct pH.
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What 0.01 N means. Mercury(II) carries two charges, so 0.01 N mercuric nitrate is 0.005 M. Each milliliter reacts with 0.01 milliequivalent of chloride, equal to 0.3545 mg of chloride (calculated), which converts titration volume directly into chloride content.
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Interferences. Bromide and iodide titrate along with chloride. Chromate, ferric, and sulfite ions interfere above about 10 mg/L, so samples high in those species need pretreatment or an alternative method.
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Calculating results. Chloride (mg/L) equals (titrant volume minus blank volume) multiplied by normality and 35,450, then divided by the sample volume in milliliters. With 0.01 N titrant, each milliliter corresponds to 0.3545 mg of chloride.
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Standardization. Standardize mercuric nitrate against a standard sodium chloride solution using diphenylcarbazone indicator, or against standard thiocyanate with ferric alum indicator, and restandardize periodically for regulated work.
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Mercury hazards and waste. Mercury compounds are toxic and harmful to aquatic life. Wear gloves and eye protection, avoid ingestion and skin contact, and collect all titration waste and rinses for hazardous waste disposal. Never pour mercury-containing solutions down the drain.
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Where it is used. Mercuric nitrate titrant is used to determine chloride in drinking water, wastewater, boiler and cooling water, and process water in labs whose permits or methods specify the mercurimetric procedure. Many labs use silver nitrate where mercury use can be avoided.
Technical Specifications
| Chemical Name |
Mercury(II) nitrate, aqueous volumetric solution |
| CAS Numbers |
7783-34-8 (mercuric nitrate monohydrate); 7697-37-2 (nitric acid, if present); 7732-18-5 (water). Confirm on SDS |
| Synonyms |
Mercuric nitrate, mercury(II) nitrate |
| Formula (active) |
Hg(NO3)2·H2O |
| Formula Weight (monohydrate) |
342.62 g/mol |
| Equivalent Weight |
171.31 (molar = 2 x normal) |
| Concentration |
0.01 N (0.005 M) |
| Mercuric Nitrate Content |
About 1.713 g/L monohydrate (calculated) |
| Chloride Equivalence |
1.00 mL = 0.3545 mg Cl⁻ (calculated) |
| Indicator |
Diphenylcarbazone (with xylene cyanol FF or bromophenol blue) |
| Titration pH |
2.3 to 2.8 (Standard Methods 4500-Cl⁻ C) |
| Interferences |
Bromide, iodide; chromate, ferric, sulfite above about 10 mg/L |
| Exposure Limit (mercury compounds, as Hg) |
OSHA PEL 0.1 mg/m³ ceiling |
| Package Size |
1 L |
Applications / Common Uses
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Chloride in drinking water: Determines chloride by mercurimetric titration.
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Wastewater testing: Measures chloride for permit reporting.
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Boiler and cooling water: Monitors chloride in industrial water systems.
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Process water QC: Checks chloride in production water.
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Method-specified analysis: Supplies titrant where methods name mercuric nitrate.
Storage, Handling & Shipping
Caution: Mercuric nitrate solution contains mercury, which is toxic and harmful to aquatic life. Avoid skin contact and ingestion; wear gloves and eye protection, and collect all waste for hazardous waste disposal.
Store tightly closed at room temperature in a secure, well-ventilated area, segregated from incompatible materials and food. Label storage areas for mercury compounds, and keep a mercury spill kit available.
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Incompatible materials: Reducing agents, strong bases, and reactive metals.
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Exposure limit (mercury compounds, as Hg): OSHA PEL 0.1 mg/m³ ceiling.
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Spill response: Contain with absorbent and collect for mercury hazardous waste disposal. Do not wash to drain.
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First aid: Skin: wash with soap and water. Eyes: rinse for several minutes. Ingestion: seek immediate medical attention.
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