Micro-chemical test for chloride: Difference between revisions
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back to [[Micro-chemical testing]] | back to [[Micro-chemical testing]] | ||
More information about the necessary equipment and materials see | |||
More information about the necessary equipment and materials see article Micro-chemistry. | |||
== Procedure == | == Procedure == | ||
The drop to be tested is acidified with very little diluted nitric acid and then a drop of silver nitrate solution is added. | The drop to be tested is acidified with very little diluted nitric acid (2M) and then a drop of silver nitrate solution is added. | ||
If Cl- is present a white precipitate of AgCl will form instantly. After exposure to light this will turn brown with time | If Cl<sup>-</sup> is present a white precipitate of AgCl will form instantly. After exposure to light this will turn brown with time( image 1). Detection limit for Cl- = 0.05µg | ||
== Further observations == | == Further observations == | ||
If sulfate is present typical silver sulfate crystals can be observed in the test drop. | If sulfate is present typical silver sulfate crystals can be observed in the test drop. | ||
== Ions that may inhibit the test or affect its | If in addition to chloride, sodium or potassium are present in the solution, typical isotropic cubes of NaCl or likewise isotropic rectangular, cruciform structures of KCl will form near the edge of the drop of the pure salt solution. | ||
== Ions that may inhibit the test or affect its sensitivity: == | |||
Iodide and bromide also | Iodide and bromide also produce white precipitates with silver nitrate solution, but these ions are not likely to be present in salt efflorescence from buildings. | ||
== Literature == | == Literature == | ||
Revision as of 13:01, 1 June 2012
Author: Christine Bläuer
back to Micro-chemical testing
More information about the necessary equipment and materials see article Micro-chemistry.
Procedure[edit]
The drop to be tested is acidified with very little diluted nitric acid (2M) and then a drop of silver nitrate solution is added. If Cl- is present a white precipitate of AgCl will form instantly. After exposure to light this will turn brown with time( image 1). Detection limit for Cl- = 0.05µg
Further observations[edit]
If sulfate is present typical silver sulfate crystals can be observed in the test drop.
If in addition to chloride, sodium or potassium are present in the solution, typical isotropic cubes of NaCl or likewise isotropic rectangular, cruciform structures of KCl will form near the edge of the drop of the pure salt solution.
Ions that may inhibit the test or affect its sensitivity:[edit]
Iodide and bromide also produce white precipitates with silver nitrate solution, but these ions are not likely to be present in salt efflorescence from buildings.
Literature[edit]
There were no citations found in the article.