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CHRIS25
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[*] posted on 6-4-2012 at 10:44
help with sodium bisulphate synthesis


I have searched the internet for days now and nothing. So I would be glad to hear from anybody who could help please.

I need to know how to react sodium hydroxide with sulphuric acid OR Sodium chloride with the same acid.

I have 18m H2So4 by the way. Usually all my knowledge about how much to use comes from the web, but strangely there is absolutely nothing to find on making NaHso4.

I have tried to learn moles and grams and conversions but really, it is too hard to grasp hence my difficulty. I have even read and read some learning materials on moles and how to convert the maths but these explanations seem to be geared to those who already know?!?!?!Mmmm

So help would be appreciated since in Ireland even Alum is hard to find, and the prices for Sodium Bisulphate are too high when one includes postage. Thankyou.
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[*] posted on 6-4-2012 at 10:58


From wikipedia

Quote:
One production method involves mixing stoichiometric quantities of sodium hydroxide and sulfuric acid which react to form sodium bisulfate and water.

NaOH + H2SO4 → NaHSO4 + H2O

A second production method involves reacting sodium chloride (salt) and sulfuric acid at elevated temperatures to produce sodium bisulfate and hydrogen chloride gas.

NaCl + H2SO4 → NaHSO4 + HCl


Doesn't get much more straight forward than that my friend. Rig up a HCl generator to get some cheap HCl(aq.) and then get the left over NaHSO<sub>4</sub> after the reaction has come to completion. Heat is required to complete the reaction with NaCl. Just look up, and follow an established proceedure for HCl production and keep the bisulfate that forms.

[Edited on 6-4-2012 by Bot0nist]




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[*] posted on 6-4-2012 at 12:21


There are threads here [this forum, use the search facility] about HCl generators, and thus about NaHSO4. But that chemical is cheap as chips and almost as OTC...

[Edited on 6-4-2012 by blogfast25]




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[*] posted on 6-4-2012 at 13:21


Quote:
NaCl + H2SO4 → NaHSO4 + HCl


I would suggest you steer away from this method if you are making more than a few grams and don't have the bits needed to handle the gas, as it becomes annoying having it fuming off a beaker for hours on end. It's really corrosive stuff and will worry the neighbours if they can see / feel it floating around for hours.
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[*] posted on 6-4-2012 at 13:53


Isn't NaHSO4 available as the swimming pool chemical "pH down?"

I wouldn't waste good NaOH to make it. I think Na2CO3 (washing soda) or even NaHCO3 ( baking soda) would be cheaper and safer.

Na2CO3 + 2H2SO4 ---> 2NaHSO4 + CO2 + H2O

Compute the required ratio by stoichiometry (yes, you will have to learn this - get somebody to help you). When you do learn it you will have made a giant stride toward being a chemist!

For baking soda, again, stoichiometry is required to determine the weight ratios.

NaHCO3 + H2SO4 ---> NaHSO4 + CO2 + H2O

Add the carbonate slowly with stirring, as there will be much fizzing.

Dilute the acid first, very carefully, by adding the acid slowly to water, with stirring. Use an ice bath if necessary.






The single most important condition for a successful synthesis is good mixing - Nicodem
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[*] posted on 6-4-2012 at 14:21


Well, a lot of people here have very kindly helped. Ys I have the formulas already from wikpedia and other sources, but as someone has said I have to learn the maths and I simply can't understand them, mostly because I have not found any clear and well explained instructions. Hence I wanted someone to kindly tell me how much NaOh and How much H2so4 I need to make about 200 grams, and do I filter and boil off the remaining water until I see the precipitate crystalize? this is all I need to know. I have plenty of acids, the H2so4 is 18 mole (96%).

By the way we do not have PH down here in Ireland and the swim pool stuff is not allowed to be sold to consumers. Very Very tight constraints here, you guys in USA are so very very lucky.
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[*] posted on 6-4-2012 at 14:33


Hi Guys just as a matter of interest, here is a quick snippet from a kids book explaining stoichiometry. And this is exactly the type of siexplanation which defies logic and why I fail to grasp the way it is explained.

Quote:
When you mix hydrogen gas (H2) and oxygen gas (O2), nothing much happens. When you add a spark to the mixture, all of the molecules combine and eventually form water (H2O). What does stoichiometry look at here? First, look at the equation. Four hydrogen (H) atoms and two oxygen (O) atoms are on each side of the equation. It's an important idea to see that you need twice as many hydrogen atoms as you do oxygen atoms. The number of atoms you need will help you figure out how much of each substance you will need to make the reaction happen. Unquote.

MY CONFUSION here is that statement that suddenly it talks about FOUR hydrogen atoms - I am not stupid I can still count, but I see only two!!!!!!!!!!!! It asks me to look at the equation - I look - I look - I stare -- I count and I count and I count NOPE still see only TWO?!?!?!? So now you understand my utter frustration with even advancing beyond pre-school!
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[*] posted on 6-4-2012 at 15:58


Quote: Originally posted by CHRIS25  
Hi Guys just as a matter of interest, here is a quick snippet from a kids book explaining stoichiometry. And this is exactly the type of siexplanation which defies logic and why I fail to grasp the way it is explained.

Quote:
When you mix hydrogen gas (H2) and oxygen gas (O2), nothing much happens. When you add a spark to the mixture, all of the molecules combine and eventually form water (H2O). What does stoichiometry look at here? First, look at the equation. Four hydrogen (H) atoms and two oxygen (O) atoms are on each side of the equation. It's an important idea to see that you need twice as many hydrogen atoms as you do oxygen atoms. The number of atoms you need will help you figure out how much of each substance you will need to make the reaction happen. Unquote.

MY CONFUSION here is that statement that suddenly it talks about FOUR hydrogen atoms - I am not stupid I can still count, but I see only two!!!!!!!!!!!! It asks me to look at the equation - I look - I look - I stare -- I count and I count and I count NOPE still see only TWO?!?!?!? So now you understand my utter frustration with even advancing beyond pre-school!


That's because atomic oxygen "O" doesn't exist under normal conditions, only O2. So an equation such as H2+O===>H2O is invalid, because there is only one oxygen atom in the equation, and thus cannot form O2. What you do is that you double the reactants in the equation (2H2+O2===>2H2O) so that there is enough oxygen in the equation to form O2, which then reacts with 2 molecules of H2 (not H!) to form 2 molecules of H2O. Now there are 4 atoms of hydrogen and 2 of oxygen.
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[*] posted on 6-4-2012 at 16:22


Quote: Originally posted by CHRIS25  
Ys I have the formulas already from wikpedia and other sources, but as someone has said I have to learn the maths and I simply can't understand them, mostly because I have not found any clear and well explained instructions. Hence I wanted someone to kindly tell me how much NaOh and How much H2so4 I need to make about 200 grams, and do I filter and boil off the remaining water until I see the precipitate crystalize? this is all I need to know.


"Give a man a fish and he will have to come back next week and ask for another. But teach him to fish..." - well you know the saying.

Giving you the "answer" is spoon feeding. Have you read about our prejudice toward that in the forum rules?

Have you cracked a chemistry book? You know, those heavy things made of paper found in libraries? If you can't be bothered to move away from your keyboard then why should we go to the effort of working out your problem?
---------------------------------------------------------

OK. I will provide a crude tutorial. Assuming you insist on using NaOH, here's the stoichiometry:

NaOH + H2SO4 ----> NaHSO4 + H2O

1. Look up the molecular weights of each of the reactants and products of the above reaction. Wiki will provide those. (Try to find out, for your own edification, how they are derived.)

2. Multiply each molecular weight for each compound by its coefficient (the whole number before each compound's formula in the equation), respectively. In this case the coefficients are all understood to be 1.

3. The 4 numbers you obtain will represent the relative weights of the products and reactants. So you can use them to calculate ratios of reactants and products.

4. Assume a basis: say 200g of NaHSO4, which you already have done. Then using the ratios calculated above find the weights of reactants to use, as well as the weight of water produced.

Let us know what you get. Good luck.


[Edited on 7-4-2012 by Magpie]

[Edited on 7-4-2012 by Magpie]

[Edited on 7-4-2012 by Magpie]




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[*] posted on 7-4-2012 at 01:27


Quote:
By the way we do not have PH down here in Ireland and the swim pool stuff is not allowed to be sold to consumers. Very Very tight constraints here, you guys in USA are so very very lucky


There's definitely at least one decent lab supplier in Ireland who'll sell to the public. They have bisulphate, at £7 a kilo. There are areas of the US where you'll need a license to own any form of laboratory equipment legally. No tubs of iodine, no concentrated peroxide etc.

Are you under 18? The rules change a lot depending on your age; e.g. a DIY store won't sell you methylated spirits or spray paint if you're not over 18, so a lab supplier isn't going to sell you anything more dangerous.

Quote:
I wanted someone to kindly tell me how much NaOh and How much H2so4 I need to make about 200 grams


You really need to look at equation balancing and converting from moles to grams, and grams to moles (it's very easy, just times one number by another, or divide one by another).

You'll get absolutely no where if you can't make an attempt at it on your own, it is one of the first things that's taught in secondary school chemistry.
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[*] posted on 7-4-2012 at 03:22


MAGPIE: I appreciate your comments, but please remember that you do not know who I am so I do find you a little inpolite in your presumptive conclusion about my apparent laziness, enough said, thankyou for that helpful tip. Oh just one thing though, teach him to fish - but provide him with a fishing rod and make sure that there are fish in the water.

WELMING: That makes it so clearer, thankyou. Trouble with many explanations on the web is that some prior knowledge is already assumed.


I found a really good site with stoichemetry and so far the explanations are are much clearer.

PEACH: I searched further - do not know where you get that £7 for a kilo, that is the price of 200 grams on the one and only site I have found, I have ordered from them before but for one product I resent paying £7 for 250 grams plus another £7 for postage!!! (www.mistraini.co.uk) based in northern ireland. So if you have something I would be grateful to know where you get the information.

Many appreciations folks.

[Edited on 7-4-2012 by CHRIS25]
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[*] posted on 7-4-2012 at 03:49


Sorry for being a little nosy, but what are you using the NaHSO4 for? If you have H2SO4, then there are almost no use of NaHSO4 that you can't replace with H2SO4. The only ones I could think of is the production of SO3, which is very dangerous and should only be attempted by experienced chemists, with the proper equipment (makeshift equipment cannot withstand SO3) But you don't need NaHSO4, FeSO4 can be used for that instead. Another use is the production of various bisulfates and pyrosulfates, which doesn't have much use themselves save of being converted into SO3. There is no source on the internet, but I would think that non-alkaline/alkaline earth metal pyrosulfates/bisulfates are unstable/cannot be formed at all.

[Edited on 7-4-2012 by weiming1998]
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[*] posted on 7-4-2012 at 04:48


Quote: Originally posted by weiming1998  
Sorry for being a little nosy, but what are you using the NaHSO4 for? If you have H2SO4, then there are almost no use of NaHSO4 that you can't replace with H2SO4. The only ones I could think of is the production of SO3, which is very dangerous and should only be attempted by experienced chemists, with the proper equipment (makeshift equipment cannot withstand SO3) But you don't need NaHSO4, FeSO4 can be used for that instead. Another use is the production of various bisulfates and pyrosulfates, which doesn't have much use themselves save of being converted into SO3. There is no source on the internet, but I would think that non-alkaline/alkaline earth metal pyrosulfates/bisulfates are unstable/cannot be formed at all.

Hi there Welming. No you are not being nosy, I have recently gone into copper and silver and pewter art, not so much jewelry as design. I have made beautiful tonal blues from various combinations of chemicals - oxidation basically of the copper metal. I need the sodium bisulphate as a replacement for jewelers pickle solution, basically it destroys all oxidations after annealing (heat treatment). Also it is an ingredient in a japanese patina which can not be bought outside of japan, though I have read otherwise recently.

I love chemistry and it was my favourite subject at school many many years ago. But like a lot of things in life, one does not always end up on the chosen path. Now after many years I find myself in the silver and copper art design area and it involved many chemicals. I have an investigative mind and so am never satisfied with a result - Ineed to understand. Hence funny as though it sounds I enjoy making chemicals and will try to avoid buying them. Most of the acetates and carbonates I have made myself - but I never needed the maths, I did it the 10th century way - eyes only without the maths. But with some chemicals I need to get it precies, and I wanted to understand the moles and atomic weights - but you know, when you are 53 you have had to learn so much technical stuff and apply yourself to adapting so much through the years that learning yet another skill can be exhausting, especially with a family and other work.

Kind regards

[Edited on 7-4-2012 by weiming1998]
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CHRIS25
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[*] posted on 7-4-2012 at 06:12


So as I have understood from Magpie and the explanations on the web which actually confuse me this is my weight for the reaction.

NaOh is 40
H2So4 is 98
NaHS04 is 138 (Monohydrate naturally)
Water is 18

This is 1 mole. So 1 times each number above happens to be the weight in grams? that is the way it is explained. I have no idea how to make ratios, I am no mathematician. I only understand that 1 mole of NaOh has a 40 something mass. So 2 gram of NaOh and 2 gram of H2So4 will give me 2 gram of NaHSo4 and some water? But that makes no sense. Relating mole masses to grams is confusing me so some explanation is needed if someone would be kind enough to walk me through it. After all most Efficient learning comes through demonstration and practical watching with elucidations, further reading cements the knowledge, not theoretical nightmarish web and book reading. Please help me that is all I ask, clarification.

[Edited on 7-4-2012 by CHRIS25]
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[*] posted on 7-4-2012 at 06:26


Ok, here is an example:

You want to calculate how much NaOH should be used if you use 20g of H2SO4 and how much bisulfate is produced. So you start by working out the molar weight, as you just posted. H2SO4=98g/mol NaOH=40g/mol, NaHSO4=118g/mol (anhydrous) and H2O=18g/mol.

Now, you put it in an equation: H2SO4+NaOH====>NaHSO4+H2O. So 98g of H2SO4 reacts with 40g of NaOH to produce 136g of NaHSO4 monohydrate (118+18). Then, you divide 98(molar mass of H2SO4) by 20(your amount of H2SO4 in grams), which equals to 4.9, and you then divide the molar weight of NaOH and NaHSO4 monohydrate by 4.9 (keeping all division the same between different numbers). The results are: 20g of H2SO4 will react with 8.16g of NaOH to produce 28.16g (simply adding the weight of the two reactants together in this equation) of NaHSO4 monohydrate.

[Edited on 7-4-2012 by weiming1998]

[Edited on 7-4-2012 by weiming1998]
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[*] posted on 7-4-2012 at 07:07


Quote: Originally posted by weiming1998  
Ok, here is an example:

You want to calculate how much NaOH should be used if you use 20g of H2SO4 and how much bisulfate is produced. So you start by working out the molar weight, as you just posted. H2SO4=98g/mol NaOH=40g/mol, NaHSO4=118g/mol (anhydrous) and H2O=18g/mol.

Now, you put it in an equation: H2SO4+NaOH====>NaHSO4+H2O. So 98g of H2SO4 reacts with 40g of NaOH to produce 136g of NaHSO4 monohydrate (118+18). Then, you divide 98(molar mass of H2SO4) by 20(your amount of H2SO4 in grams), which equals to 4.9, and you then divide the molar weight of NaOH and NaHSO4 monohydrate by 4.9 (keeping all division the same between different numbers). The results are: 20g of H2SO4 will react with 8.16g of NaOH to produce 28.16g (simply adding the weight of the two reactants together in this equation) of NaHSO4 monohydrate.

[Edited on 7-4-2012 by weiming1998]

[Edited on 7-4-2012 by weiming1998]



Ok now I've got it, your simple clear explanation has done for me what three days of internet reading did'nt. thankyou ever so much, it is all so clear now. Except for one tiny tiny thing, you gave 118 for the monohydrate, whereas wikpedia gave 138 and 126 for anhydrous, I suppose that your information is more accurate or that small discrepencies do not really matter in my situation.

Also just to be absolutely certain H2SO4 moles/mass is always given for concentrated solutions. So if I read 50 for an acid I simply assume that this is for the concentrated solution.

But many appreciations for your explanation I mean that.
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[*] posted on 7-4-2012 at 07:36


NaOH + H2SO4 → NaHSO4 + H2O

NaOH: 39.9971 g/mol
Suphuric: 98.079 g/mol
Bisulphate: 120.06 g/mol (anhydrous)
Water: 18.01528 g/mol

1 mole NaOH + 1 mole H2SO4 -> 1 mole NaHSO4 + 1 mole H20

39.9971 + 98.079 -> 120.06 + 18.01528

Looking at each side, the left:
39.9 + 98 = 138g in total

And then the right:
120 + 18 = 138g in total

200g of bisulphate is 200 / Bisulphate: 120.06 g/mol (anhydrous) = 1.66583375 moles

1.66583375 x NaOH: 39.9971 g/mol = 66.62g NaOH
1.66583375 x Suphuric: 98.079 g/mol = 163.38g Sulphuric

The bisulphate comes out as anhydrous bisulphate. But, as the other product is water, and bisulphate can absorb it to form hydrates, you actually get damp bisulphate rather than dry bisulphate and a puddle of water.

When talking about sulphuric, is it assumed you mean 100% H2SO4. Although, in practice, only 98% is commonly available and it tends to drop a few percent. The missing 2% is mainly water, which can't be removed from the sulphuric without extra things being added to it's purification. The difference isn't usually a problem. 98% is used in universities and industry all the time; it's called CP (commercially pure), or in other words, 'good enough'.

It's physically impossible to measure out precisely 1 mole of NaOH and 1 mole of sulphuric at home. Not only because the measurements would need to be insanely precise (accurate to trillionths and trillionths of a gram), but both of those chemicals suck up moisture and CO2 from the air.

Instead, people will usually pick one to be 'the limiting reagent' and the other 'the excess', even if it's only by a tiny amount. E.g. if you're not sure of your sulphuric percentage, you might add an extra 10%, knowing that you'll probably get a bit of sulphuric left unreacted, but that all of the hydroxide would have reacted.

[Edited on 7-4-2012 by peach]
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[*] posted on 7-4-2012 at 08:27




The bisulphate comes out as anhydrous bisulphate. But, as the other product is water, and bisulphate can absorb it to form hydrates, you actually get damp bisulphate rather than dry bisulphate and a puddle of water.


Peach another great explanation which actually cements this all together - you are appreciated also. I am learning. Although about what you said above, I usually filter and allow the residue to dry, I will pour 50/50 distilled water and methylated spirit into the filter after all the water has dripped away. Reasoning behind this is to both assist drying process, extracting water and also to wash away any miniscule impurities that might exist in the precipitate) Do you see anything wrong with all this. Kind regards, Chris.

[Edited on 7-4-2012 by peach][/rquote]

[Edited on 7-4-2012 by CHRIS25]
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[*] posted on 7-4-2012 at 12:03


Quote:
pour 50/50 distilled water and methylated spirit into the filter


Only thing you might want to be careful of there is that bisulphate is quite soluble in water (500g per litre at 0C and an impressive kilo per liter at 100C), more so than table salt.

It does react with ethanol to produce sodium ethyl sulphate, although the reaction is not particularly quick at room temperature. I left some ethanol sat over bisulphate on a radiator at 45C for 12h and I think I got about 25% sodium ethyl sulphate from memory.

When the bisulphate absorbs that water that's also being produced (which it will do), you'll get the monohydrate out. Which is a solid up to 50C. Since you'll be making a pickling solution with the bisulphate, there's not too much of problem with it being the monohydrate, as it'll be getting lots more water when it's dissolved. If you know it's the monohydrate as you're weighing it, all is fine.

Bisulphate has a pH of 1 in solution (rather acidic), so make NaOH your limiting reagent and add a slight excess of sulphuric.

You could recrystallise the bisulphate, but I suspect that's excessive for a pickling solution.

Have you got any photos, or could you take some, of your work? Some colourful chemistry to jazz up the forum is always nice. Nicer than looking at another colourless or brown flask anyway... :D

Metal working was about the first thing I was seriously interested in. Bought myself MIG and oxy/acet welding gear with saved up birthday cards in my early teens, built a gas furnace, bought a lathe. I worked making custom electric gates and railings for people, but they were always kind of stereotypical things since I was doing it for someone else. Always interested in the more colourful things that can be done aside from the ultra precise world of CNC. Jewellery is interesting as well, all the chemistry of the gems, the splitting, choosing a form from the rough... I particularly like the 1940-50's things that appear on the antiques road show.

{edit}Oh, I forgot to mention. Be careful adding these things to each other in concentrated forms. They will release a lot of heat, quickly! It is the thing third degree burns are made of. You may want to keep them above 50C, such that they don't solidify until fully reacted, and add the NaOH, a small bit at a time (start with a few pellets or perls), to the sulphuric; such that the heat will spread out and you don't have hot NaOH in contact with the glass. Be very careful with your face and eyes (I would suggest you have a face shield if doing this kind of thing; about £10*). It is likely going to spit. You do not want that in your eyes! May be easier to do it in metallic container, that's less likely to shatter and that can be bumped to knock the solid out.

*My brother just paid £3k to have his eyesight corrected, never mind replaced.

[Edited on 7-4-2012 by peach]
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[*] posted on 7-4-2012 at 12:46


Hallo Peach, yep I just bust two glass jars. Did the mixture outside, now I know you are supposed to add acid to water so I assumed adding acid to Naoh was ok, I was utterly wrong. So I tried it the other way around this time very slowly. I put in just a quarter of a teaspoon of Naoh to the acid at first. Nothing happened. I waited about 5 minutes and it did not react so I thought ok then this is safe to add the whole lot. MMmmmm I was so utterly wrong. Everything was safe though, no splashes or anything just two broken glasses.

So how should I actually mix it. never thought that I would have to ask this? I am using 33g of Naoh and 81g of concentrated H2So4.

Ok thanks for the tip about alchohol. i will not do that. Just get the precipitate and that's it.

Oh one question which has thrown me completely. On many websites I noticed that they said Naoh and H2So4 gives sodium sulphate. I also notice that this always involved a 2 before the Naoh. I understand this but this is theory, what does this 2 mean in actual reality practise. Does it mean that you add twice as much NaOh to get sodium sulphate instead of the sodium bisulphate?

regards, chris.
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[*] posted on 7-4-2012 at 12:55


=======================================
Metal working was about the first thing I was seriously interested in. Bought myself MIG and oxy/acet welding gear with saved up birthday cards in my early teens, built a gas furnace, bought a lathe. I worked making custom electric gates and railings for people, but they were always kind of stereotypical things since I was doing it for someone else. Always interested in the more colourful things that can be done aside from the ultra precise world of CNC. Jewellery is interesting as well, all the chemistry of the gems, the splitting, choosing a form from the rough... I particularly like the 1940-50's things that appear on the antiques road show. ======================

Metal working you did was quite industrial, out of my league. The 1940 50 things are quite intricate, I am not that skilled yet, though I have made a number of pewter brooches for my wife and combined them with copper decorations. My children and I have collected 20 kg of lead off of one single beach in the last 5 years. we melted and purified everything into ingots. That's how my metal journey began. Copper is incredibly fascinating, it is like no other metal in the colours that you can achieve (except maybe silver) Producing patinas on copper is really exciting. I have managed various controlled tones of beautiful blues via copper acetate and ammonia mixtures. Greens are too easy and I find them boring but so much experimentation has been done, I am trying to get purple. Also managed rainbows, beautiful, this comes via the chlorides, although with careful heating you can achieve the same but the depth and range of colours are reduced when you heat. The trick is to combine a chemical patina with a heat patina. I use a borax to protect but this is proving a little difficult in some experiments hence my need for sodium bisulphate - if I can create it without scaring the life out of me. Anyway if you are ever interested in colourful things then if I can help please feel free.


[Edited on 7-4-2012 by CHRIS25]
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peach
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[*] posted on 7-4-2012 at 12:58


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So how should I actually mix it. never thought that I would have to ask this?


The way you are mixing them is actually, given what you're making, very dangerous.

People will say acid to water when they are using dilute acid. You are using something around 18 times more concentrated than bench acid, and it's not going into water, it's reacting with the NaOH, making it even hotter.

Do you mean kitchen glasses? If so, those aren't borosilicate glass, and can't withstand drastic temperature changes well at all.

This is something I'd do over the course of hours or a day, walking past and adding a scoop more. You could also consider doing it in something like a paint can, which won't crack and can be knocked out afterwards.

It is genuinely dangerous, mind you don't get splashed with that. I've had boiling, concentrated sulphuric on me before. As soon as a few drops spattered onto the skin of my leg, it burnt a mark into it that was there three months later; even though I had a hosepipe beside me and rinsed it off about 2 or 3 seconds later. It's too hot and too concentrated to be anywhere near skin. Molten NaOH will dissolve laboratory glass, which is somewhat unique.

Quote:
Oh one question which has thrown me completely. On many websites I noticed that they said Naoh and H2So4 gives sodium sulphate. I also notice that this always involved a 2 before the Naoh. I understand this but this is theory, what does this 2 mean in actual reality practise. Does it mean that you add twice as much NaOh to get sodium sulphate instead of the sodium bisulphate?


Yup.

The bisulphate has 'too much sulphuric' if you like (or... not enough NaOH). It wants more NaOH to fully neutralise, since bisulphate is not neutral; it's acidic when it's dissolved in water, so it'll carry on reacting with anything alkaline.

[Edited on 7-4-2012 by peach]
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CHRIS25
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[*] posted on 7-4-2012 at 13:02


But i thought that one should never ever use anything other than an inert container for chemical reactions, regardless of its strength, ie, plastic or glass? Are you sure that I can use something that is made from stainless steel?
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[*] posted on 7-4-2012 at 13:11


It all depends which chemical and which container it is.

Concentrated hydrofluoric acid will eat through the walls of laboratory glass in under a minute. And metals. But it does precisely nout all to PTFE (teflon, plastic).

Industrially, they can't use glass and plastic for everything, they need to use metal where ever possible to make it structurally strong enough. Stainless is common.

Stainless is, at the end of the day, iron with some other bits added. Things can leach the iron from the stainless, but for whole lot of applications, it's not a problem. For really corrosive things, they might use monel, an alloy that is mainly nickel. Or plate it with something. E.g. copper is resistant to sulphuric provided it's not copper oxide.

I made a few litres of benzene last year. The method I used was to heat sodium benzoate food preservative with KOH over a camping stove. The can was absolutely fine, even though it was at hundreds of degrees and being knocked out between each go. Whereas melting NaOH in laboratory glass dissolves the glass.

[Edited on 7-4-2012 by peach]
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[*] posted on 7-4-2012 at 13:37


Ok interesting I never knew any of that. Stainless steel by the way is Iron with a little chromium, 2-7% i believe. So I can use plastic and teflon with hydrochloric acid and stainless steel saucepan with sulphuric acid and sodium hydroxide. I will check up on aluminium (the army camp containers). they are cheap here and I used them for lead, but had to throw as soon as it cooled down.
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