Reactivity of Ammonia

[Theophrastus]

As many know from experience, single and double displacement reactions, are a common way of synthesising needed, and/ or interesting compounds. In this, a knowledge of the activity series is required, however, I have run into a problem: where on the activity series, would one place ammonia, or rather the ammonium ion? It was is one of few nonmetal cations, and as such, would belong on the metal activity series, but where? Any thoughts?

[max.yevs]

in terms of reactivity with an acid, one whould have to suppose it would be right above hydrogen... but there's the question of ammonia vs. ammonium..when reacting with non-acids. for example, when reacting with chlorine, hydrogen would probably be more reactive... because ammonia + chlorine does not make ammonium chloride... (it makes dangerous explosive NCl3)

[Theophrastus]

I meant it in a metallic sense; for example copper, is more noble than hydrogen, and as such, does not displace it. The ammonium ion, in a similar way, takes the same role as hydrogen, that of a cation, in binary compounds, and as such, would it not have its own place on the activity series? For example, were I to have on hand ammonium sulfate, adding magnesium, this displace the ammonium ion however, its precise place, I am unsure of.

 

(NH4)2SO4 + Mg > 2NH3 + H2 + MgSO4

[max.yevs]

I would think that ammonium is just slightly more reactive than hydrogen in the metallic sense, i say so because ammonium ions usually exist in equilibrium with ammonia and hydronium ions.

 

I think it is safe to assume that most of the things an acid will react with, an ammonium salt will also react with, although less violently... but you might want to wait until you get some more responses

[CaptainPanic]

Are you perhaps trying to oversimplify the world of chemistry?

 

Personally, I never heard of "double displacement reactions", so I googled it, and found (how surprising) a wikipedia website about it. It shows a wide variety of reactions: organic chemistry (olefins) and redox, and acid/base reactions.

 

I suggest that you study the individual types of reactions rather than to try to capture everything in a single comprehensive list. The example in the post of Theophrastus is a redox reaction. Rather than to try to predict the reaction from some list of reactivity, I suggest that you study the theories of redox reactions.

 

The world of chemistry is, unfortunately, not always as linear as you seem to be hoping for. It's full of exceptions and components that behave different that you'd expect from the books.

 

Just out of curiosity guys (max.yevs, Theophrastus), what level of chemistry education are you at (what are you doing and what did you finish)? You seem to post a lot here.

 

Personally, I'm a chemical process engineer. Not too great on the chemistry side, good at engineering.

[John Cuthber]

"Ammonium" as a metal doesn't have much of an existence, but a solution of it in mercury does. Here's a reference.

http://www.vias.org/encyclopedia/chem_ammonia_salts.html

 

Since it decomposes in water to give hydrogen I guess it can be viewed as reducing the water but that's not clear.

[Theophrastus]

I didn't mean exactly as a metal, but rather as a cation, as the ammonium ion is the only nonmetallic cation, with the exception of hydrogen. I was hoping that ammonia, too had a place on the activity series, just as hydrogen, despite its nonmetallic nature. You are right that this is for some redox chemistry I'm interested in performing, as I generally find that practice without any supporting theoretical work, is like a mad scramble in the dark, with no light to lead one. Certainly, there have been cases in which such a strategy has prevailed, but I generally dislike such methods, so I was looking for some help.

In regards to Captain Panic's post, in regards to any formal chemistry education, I have currently just begun high school, and as such have not had any exposure in a school setting, however I have been reading up a lot on chemistry: I'm currently starting to do some work from an AP textbook I have obtained, hoping to do the test earlier than most do, if possible. I've also begun to tread on some experimental work, however as I proclaimed in my first post, I am woefully inexperienced (in the literal sense of the word) in that field, and as such, when performing more dangerous work, generally consult with one of my family friends (a former physicist) as well as this forum. (returning to the concept at hand) Any thoughts?

 

Note: Now that I think of it, I could through ascending activity of metals predict a relative position for ammonia...

[UC]

I didn't mean exactly as a metal, but rather as a cation, as the ammonium ion is the only nonmetallic cation, with the exception of hydrogen.

 

Since when? You're missing a vast amount of chemistry somewhere.

 

"Ammonium" as a metal doesn't have much of an existence, but a solution of it in mercury does. Here's a reference.

http://www.vias.org/encyclopedia/chem_ammonia_salts.html

 

Since it decomposes in water to give hydrogen I guess it can be viewed as reducing the water but that's not clear.

 

That sounds exceedingly dated. I suspect the main component is sodium amide.

[Theophrastus]

Ah, you are right... I'm missing the hydromium ion, as well as vinyl, in regards to nonmetallic cations. Anything else? I'm at a loss. Its a shame that herein lies an exception, as these exceptions are more than rather annoying. Totally unrelated, but I'm actually rather surprised you haven't heard of double- displacement reactions, it is one of the basic kinds. I suppose you probably learned of their separate classes, neutralization, and precipitation reactions. Shame...

thanks for the help,

 

,Theo

Edited April 1, 2009 by Theophrastus
addition of content

[hermanntrude]

a "double displacement" reaction is better described as a redox reaction.

 

An example of a polyatomic cation:

 

[ce] H3O+

NH4+

NO2+

UO2+

VO2+[/ce]

 

although those last two could be considered metallic in that they contain a metal. There's also [ce]Hg2^2+[/ce]

[UC]

Ah, you are right... I'm missing the hydromium ion, as well as vinyl, in regards to nonmetallic cations. Anything else? I'm at a loss. Its a shame that herein lies an exception, as these exceptions are more than rather annoying. Totally unrelated, but I'm actually rather surprised you haven't heard of double- displacement reactions, it is one of the basic kinds. I suppose you probably learned of their separate classes, neutralization, and precipitation reactions. Shame...

thanks for the help,

 

,Theo

 

You seem to be confusing simple high school level inorganic chemistry with all of chemistry. There is no sharp line. There are carbocations of all kinds, polyatomic chalcogen cations, metal clusters, substituted and quaternary ammoniums, ylides, phosphoniums, all manner of metal complexes, etc.

 

There is also no hard line between ionic and covalent. Things can have partial positive charges and solvent choice makes a world of difference.

 

a "double displacement" reaction is better described as a redox reaction.

 

Actually, a "single displacement" reaction is a redox reaction using an element. A double displacement is a metathesis reaction, and as far as inorganics go, it's only considered to have happened when there is a precipitate. If you wanted to do the reduction of say hexachloroplatinate anion by hydrazinium sulfate, I think the high school way to look at these reactions would crap its pants. Then there are olefin metathesis reactions using things like grubbs' catalyst, but let's not get into that.

Edited April 2, 2009 by UC

[hermanntrude]

You seem to be confusing simple high school level inorganic chemistry with all of chemistry. There is no sharp line. There are carbocations of all kinds, polyatomic chalcogen cations, metal clusters, substituted and quaternary ammoniums, ylides, phosphoniums, all manner of metal complexes, etc.

 

There is also no hard line between ionic and covalent. Things can have partial positive charges and solvent choice makes a world of difference.

 

 

 

Actually, a "single displacement" reaction is a redox reaction using an element. A double displacement is a metathesis reaction, and as far as inorganics go, it's only considered to have happened when there is a precipitate. If you wanted to do the reduction of say hexachloroplatinate anion by hydrazinium sulfate, I think the high school way to look at these reactions would crap its pants. Then there are olefin metathesis reactions using things like grubbs' catalyst, but let's not get into that.

 

I knew that:mad:

[UC]

I knew that:mad:

 

Sorry, that wasn't directed at you. I'm know you know, but should I have left it uncorrected?

[hermanntrude]

yes

 

 

[editorial note: Hermann is feeling sarcastic today]

[Theophrastus]

To summarise the lesson I have learned today, I suppose I can include two things:

1) Science is not nearly as orderly as a beginner (myself) might expect

2) Sarcasm on a forum is actually rather fun to read (lol)

 

Thanks for the input!

[CaptainPanic]

To summarise the lesson I have learned today, I suppose I can include two things:

1) Science is not nearly as orderly as a beginner (myself) might expect

2) Sarcasm on a forum is actually rather fun to read (lol)

 

Thanks for the input!

 

1) Science is in fact very orderly, but not on the level where you expect it.

Chemistry is governed by the laws of physics. Atoms have a certain size, and there exist many intra and inter atomic forces (also some forces that you probably never heard of)... these cause attraction and repulsion depending on the distance between (sub)atomic particles.

These things are orderly... and can be modeled.

 

But what you're trying to do is to find order in systems which consist of 3-5 types of atoms (which themselves consist of several neutrons, protons and electrons in varying types of orbits, with the atoms at varying distances and having several types of interactions). This is already quite a complex system, and therefore perhaps less orderly.

 

2) True. Some sarcasm concerning point 1) Chemistry is ruled by the laws of physics, which is why it's so logical that the subjects are split up in school.

[hermanntrude]

concerning sarcasm, on an old forum I used to frequent, we had a font colour known as "sarcastic purple".

[John Cuthber]

Since when? You're missing a vast amount of chemistry somewhere.

 

 

 

That sounds exceedingly dated. I suspect the main component is sodium amide.

 

That's an interesting concept.

Electrolysis of a solution of ammonium chloride in water giving a sodium compound.

Here's a relatively recent reference to a related compound, just to spice things up a bit.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THS-44VFYDR-15&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1a40443903d2e0c998a7cf6732838681

[UC]

That's an interesting concept.

Electrolysis of a solution of ammonium chloride in water giving a sodium compound.

Here's a relatively recent reference to a related compound, just to spice things up a bit.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THS-44VFYDR-15&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1a40443903d2e0c998a7cf6732838681

 

The older reference used sodium amalgam and concentrated NH4Cl solution. I see no electrolysis. Take note that this reference is for quaternary ammoniums and uses electrolysis. Perhaps the result of the older procedure contained a small fraction of the ammonium compound, but would have been far from pure.

[John Cuthber]

Sorry, I had intended to add this (old) reference to the original post.

http://pubs.acs.org/doi/abs/10.1021/ja01960a005

No sodium here.