Micro-chemical test for ammonia: Difference between revisions

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Author: [[user:CBlaeuer| Christine Bläuer]]<br>
Author: [[user:CBlaeuer| Christine Bläuer]]<br>


back to [[Micro-chemical testing]]
For more information on the required equipment and materials see the Micro-chemistry article.
== Principle ==
When dissolving a salt containing ammonium  in an alkaline 2M NaOH solution, gaseous ammonia (NH<sub>3</sub>) is liberated which has a typical smell and will change the color of a previously wetted yellow pH indicator paper to green or blue.
== Procedure ==
Add a drop of 2M sodium hydroxide, i.e., caustic soda, to a drop of the sample solution and immediately hold a wetted pH indicator paper directly above it into the released vapors.


More information about the necessary equipment and materials see Article Micro-chemistry.
Principle
When dissolving a salt containing Ammonia in NaOH alkaline vapors extrivate having a typical odor and which will change the color of a previously wetted yellow pH indicator paper to green or blue.
Procedure
Add a drop of  caustic soda solution to a drop of the sample solution and immediately hold a wetted pH indicator paper directly above it into the extrivating vapors.
or  
or  
put drop of caustic soda solution on an object slide and then put one grain of the salt into it. Hold a wetted pH indicator paper directly above the preparation into the extrivating vapors, while the salt is still dissolving.
Indications from the pH-value of the salt solution
The pH value of an aqueous Nitrammite solution is slightly acidic (circa pH 5). If the sample solution is acidic this is no proof of Ammonium nitrate but it can be a first indication.


put drop of sodium hydroxide solution (NaOH 2M ) on a microscope slide and then put one grain of the salt into it. Hold a wetted pH indicator paper directly above the preparation into the liberated vapors, while the salt is still dissolving.
'''Indications from the pH-value of the salt solution'''
The pH value of an aqueous solution of nitrammite [NH<sub>4</sub>,K (NO<sub>3</sub>)], (also known as gwihabaite) is slightly acidic (circa pH 5). If the sample solution is acidic this is no proof for the presence of ammonium nitrate but it is a first indication.


== Literature ==
== Literature ==
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[[category:Bläuer,Christine]][[category:inProgress]][[category: microchemistry]]
[[category:Bläuer,Christine]][[category:approved]][[category: microchemistry]]

Latest revision as of 20:21, 24 November 2017

Author: Christine Bläuer

back to Micro-chemical testing

For more information on the required equipment and materials see the Micro-chemistry article.


Principle

When dissolving a salt containing ammonium in an alkaline 2M NaOH solution, gaseous ammonia (NH3) is liberated which has a typical smell and will change the color of a previously wetted yellow pH indicator paper to green or blue.

Procedure

Add a drop of 2M sodium hydroxide, i.e., caustic soda, to a drop of the sample solution and immediately hold a wetted pH indicator paper directly above it into the released vapors.

or

put drop of sodium hydroxide solution (NaOH 2M ) on a microscope slide and then put one grain of the salt into it. Hold a wetted pH indicator paper directly above the preparation into the liberated vapors, while the salt is still dissolving.

Indications from the pH-value of the salt solution The pH value of an aqueous solution of nitrammite [NH4,K (NO3)], (also known as gwihabaite) is slightly acidic (circa pH 5). If the sample solution is acidic this is no proof for the presence of ammonium nitrate but it is a first indication.

Literature