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HgDinis25 - 18-4-2015 at 13:36

Hey,

So, I have a few questions that have been bugging me for a while that I hope someone can answer them.

First one is about Piranha Solution. Every source I find with a procedure to prepare said solution advise to always add the Hydrogen Peroxide to the Sulfuric Acid, never the other way around. They claim that if the concentration of Hydrogen Peroxide is too high an explosion might happen.
However, wouldn't adding the H2O2 to the H2SO4 allow the formation of much concentrated H2O2? The Acid would absorb the water making almost 100% H2O2 on the first drops added.
However, adding the acid to the H2O2 wouldn't cause that. There would always be plenty of water. Can anyone explain, please?

Second question is about Acrylic Acid. Does the polymerization of Acrylic Acid to Polyacrylic Acid happen at room temperature? What about Sodium Acrylate? Is it possible to make Sodium Acrylate and have it polymerize into Sodium Polyacrylate absent a catalyst of some sort (or high temperatures for that matter)?

Last, lest interesting question, is there any data out there about Lead(II) Nitrate explosivity? Is it explosive at a certain temperature? I ask this because it ranks 1 in the reactivity code of the fire diagram and I haven't figured out why.

Thanks in advance,
HgDinis25

Lambda-Eyde - 18-4-2015 at 14:31

Quote: Originally posted by HgDinis25  
First one is about Piranha Solution. Every source I find with a procedure to prepare said solution advise to always add the Hydrogen Peroxide to the Sulfuric Acid, never the other way around. They claim that if the concentration of Hydrogen Peroxide is too high an explosion might happen.
However, wouldn't adding the H2O2 to the H2SO4 allow the formation of much concentrated H2O2? The Acid would absorb the water making almost 100% H2O2 on the first drops added.
However, adding the acid to the H2O2 wouldn't cause that. There would always be plenty of water. Can anyone explain, please?

There's also plenty of H2SO4, isn't there?
Quote: Originally posted by HgDinis25  
Last, lest interesting question, is there any data out there about Lead(II) Nitrate explosivity? Is it explosive at a certain temperature? I ask this because it ranks 1 in the reactivity code of the fire diagram and I haven't figured out why.

Because it is, like all other nitrates, a relatively powerful oxidizer, I'd reckon.

HgDinis25 - 18-4-2015 at 14:39

@Lambda-Eyde
Quote:

There's also plenty of H2SO4, isn't there?


Really? So we're momentarily making a solution of Anhydrous Hydrogen Peroxide in Sulfuric Acid. That sounds way safer and less explosive than a solution of Sulfuric Acid and Hydrogen Peroxide in water...
Quote:

Because it is, like all other nitrates, a relatively powerful oxidizer, I'd reckon.


That's plain wrong. Sodium Nitrate ranks 0 in the reactivity code. Potassium Nitrate ranks 0 in the reactivity code. Lead(II) Nitrate must be different some-how, just like Mercury(II) Nitrate for instance.

[Edited on 18-4-2015 by HgDinis25]

RareEarth - 18-4-2015 at 14:46

Quote: Originally posted by HgDinis25  
@Lambda-Eyde

Quote:

There's also plenty of H2SO4, isn't there?


Really? So we're momentarily making a solution of Anhydrous Hydrogen Peroxide in Sulfuric Acid. That sounds way safer and less explosive than a solution of Sulfuric Acid and Hydrogen Peroxide in water...

[Edited on 18-4-2015 by HgDinis25]


I'm going to assume you're being sarcastic, but just in case you're not...

Concentrated hydrogen peroxide is highly explosive.... not to mention anhydrous hydrogen peroxide. 90% hydrogen peroxide is used as rocket fuel. If you didn't know this, then I suggest being very careful about what you do so as to not blow yourself up.

HgDinis25 - 18-4-2015 at 14:48

@RareEarth,

Hahahaha you're funny :P

Lambda-Eyde - 18-4-2015 at 15:09

Jesus christ man, do you expect people to help you if you're just going to be a sarcastic dick? Plug out your internet cable and put it in when you're in a better mood.

HgDinis25 - 18-4-2015 at 15:17

Quote: Originally posted by Lambda-Eyde  
Jesus christ man, do you expect people to help you if you're just going to be a sarcastic dick? Plug out your internet cable and put it in when you're in a better mood.


Hey calm down, sorry if I came down too sarcastic. You have to admit though, that you could have given a better answer than just "There's also plenty of H2SO4, isn't there?"

Anyway, don't take it personal ;)

[Edited on 18-4-2015 by HgDinis25]

Lambda-Eyde - 19-4-2015 at 00:38

I was referring more to your answer to RareEarth. When asking random people on the internet to help you further your understanding you should be a little bit more humble.

My answer should be more than sufficient to answer your question. If you add, say, 1 mL 30% hydrogen peroxide to 100 mL sulfuric acid, it should be obvious that there won't be any "100% hydrogen peroxide" in your solution. It is diluted by the large amounts of sulfuric acid present.

I assumed that other nitrates also scored a 1 on the yellow NFPA square, but apparently they don't. So now I'm also interested in hearing an answer to your question about lead nitrate.

HgDinis25 - 19-4-2015 at 03:24

@Lambda-Eyde,

Remember that you're adding H2O2 dropwise. When each drop gets in contact with Sulfuric Acid the water immediately gets absorbed, with a rise in temperature. As it gets absorbed the concentration on the drop may rise to 100%.

Will it get diluted in Sulfuric Acid? Maybe, but that sounds A LOT more danger than adding the Sulfuric Acid to the Hydrogen Peroxide. Your answer was empty. I was asking why every procedure claims that adding the Peroxide to the Acid is a lot safer and avoid explosions than adding the Acid to the Peroxide.

You didn't say anything about this. You basically counterpointed my assumption that 100% H2O2 could be formed. Thats not even half of the problem.

[Edited on 19-4-2015 by HgDinis25]

Milan - 19-4-2015 at 03:40

So in the procedure you are adding one chemical to the other drop-wise and H2O2 has a chance of exploding in both cases, right?
If so wouldn't it be safer to have one drop of H2O2 explode rather than a bigger volume, or am I missing something?

HgDinis25 - 19-4-2015 at 03:57

Quote: Originally posted by Milan  
So in the procedure you are adding one chemical to the other drop-wise and H2O2 has a chance of exploding in both cases, right?
If so wouldn't it be safer to have one drop of H2O2 explode rather than a bigger volume, or am I missing something?


If they both had the same chance of exploding, than yes a drop is much better that a million drops :D

However, I don't think adding the Sulfuric Acid dropwise to the Hydrogen Peroxide has the same level of dangerousness as adding Hydrogen Peroxide dropwise to Sulfuric Acid.

Adding the Sulfuric Acid to the H2O2 wouldn't increase its concentration (as claimed by many procedures I encounter). It's like the old Acid to Water never Water to Acid.

Milan - 19-4-2015 at 04:10

Quote: Originally posted by HgDinis25  
Quote: Originally posted by Milan  
So in the procedure you are adding one chemical to the other drop-wise and H2O2 has a chance of exploding in both cases, right?
If so wouldn't it be safer to have one drop of H2O2 explode rather than a bigger volume, or am I missing something?


If they both had the same chance of exploding, than yes a drop is much better that a million drops :D

However, I don't think adding the Sulfuric Acid dropwise to the Hydrogen Peroxide has the same level of dangerousness as adding Hydrogen Peroxide dropwise to Sulfuric Acid.

Adding the Sulfuric Acid to the H2O2 wouldn't increase its concentration (as claimed by many procedures I encounter). It's like the old Acid to Water never Water to Acid.


That is correct, but might it be that they recommend H2O2 to Sulfuric Acid because of safety paranoia, maybe, something similar to "it doesn't matter what is the chance of explosion in this or that procedure, if this is more dangerous when it goes off we'll do the other procedure"(I'm not quoting anyone). Though this might be just an incorrect assumption on my part.

vmelkon - 20-4-2015 at 09:53

Quote: Originally posted by HgDinis25  
The Acid would absorb the water making almost 100% H2O2 on the first drops added.


I imagine you are talking about adding 30% H2O2 to 98% H2SO4.
I have only made weak solutions using 3% H2O2 and my H2SO4 is probably 95%.

Why would you get a 100% H2O2 drop? I imagine the entire drop would dissolve into the H2SO4.

HgDinis25 - 20-4-2015 at 09:57

@Milan,
Well, I hope it's not that. Otherwise it would be quite ridiculous... Anyway, thanks, I hadn't thought about that.

@vmelkon,
I was merely postulating something that could happen. The all point is that adding the acid to the peroxide seems a lot safer than adding the peroxide to the acid...

vmelkon - 20-4-2015 at 10:02

Quote: Originally posted by HgDinis25  
@Milan,
@vmelkon,
I was merely postulating something that could happen. The all point is that adding the acid to the peroxide seems a lot safer than adding the peroxide to the acid...


I would think so since the H2O2 contains large amounts of water, it is like adding H2SO4 to pure water.

HgDinis25 - 24-4-2015 at 14:54

Any more help?