tom haggen
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NH4NO3 and KNO3
I was just curious. Due to the basic nature of potassium nitrate, and the acidic nature of ammonium nitrate, would mixing the two nitrate salts cause
them to decompose slowly over long periods of time?
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BromicAcid
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Potassium nitrate solutions are actually slightly acidic, a 40% solution in water has a pH of 6.5 which is only very very slightly acidic as you know.
Good MSDS on the 40% solution
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tom haggen
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I guess I was just thrown off because potassium is an alkaline metal.
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Pyrovus
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NH4NO3 will slowly decompose on it's own, as a result of the equilibrium:
NH4+ <-> NH3 + H+
Though this equilibrium lies to the left, some of the ammonia formed will escape into the atmosphere, so the system will be continually losing
ammonia.
There also exists the equilibrium:
H+ + NO3- <-> HNO3
Which although this too lies predominately to the left, it to a small extent helps to hinder the reverse reaction of the first equilibrium by removing
some of the protons formed. Adding KNO3 provides more nitrate ions, which will increase the number of protons removed by the second equilibrium.
So the net effect should be that KNO3 should act as a catalyst (albeit not a very good one) for the
decomposition of ammonium nitrate into ammonia and nitric acid.
[Edited on 30-6-2004 by Pyrovus]
Never accept that which can be changed.
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Darkfire
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| Quote: | Originally posted by tom haggen
I guess I was just thrown off because potassium is an alkaline metal. |
Yes, the K ions like to seperate
fully from the NO3 ions as well as not changing the waters ph. But the same is true for the NO3 ions in relations to the K ions and the water thus the
pH is close to 7.
This is becuase both the K ions and NO3 ions are both "strong". If it was a compound like NH4Cl or KCOOH you would expect a greater pH
change.
\"I love being alive and will be the best man I possibly can. I will take love wherever I find it and offer it to everyone who will take it. I
will seek knowledge from those wiser and teach those who wish to learn from me.\" Duane Allman
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