Standard Methods: 4500-Cl- C: Chloride by Mercuric Nitrate Method
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Official Method Name
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4500-Cl- C. Mercuric Nitrate Method |
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Current Revision
| Standard Methods Online |
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Media
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WATER |
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Instrumentation
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Titration with Color Indicator |
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Method Subcategory
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Inorganic |
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Method Source
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Citation
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Brief Method Summary
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Chloride can be titrated with mercuric nitrate, Hg(NO3)2, because of the formation of soluble, slightly dissociated mercuric chloride. In the pH range 2.3 to 2.8, diphenylcarbazone indicates the titration end point by formation of a purple complex with the excess mercuric ions. Xylene cyanol FF serves as a pH indicator and end-point enhancer. |
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Scope and Application
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The end point of this method is easier to detect than that of the argentometric method. |
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Applicable Concentration Range
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Interferences
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Bromide and iodide are titrated with Hg(NO3)2 in the same manner as chloride. Chromate, ferric, and sulfite ions interfere when present in excess of 10 mg/L. |
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Quality Control Requirements
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See Section 4020 Quality Assurance/Quality Control. |
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Sample Handling
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Collect representative samples in clean, chemically resistant glass or plastic bottles. The maximum sample portion required is 100 mL. No special preservative is necessary if the sample is to be stored. |
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Maximum Holding Time
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28 days (regulatory); See Section 1060 |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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