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Author: Subject: How to make a 1 Mole Sodium Hydroxide (NaOH) solution.
JoeyJoystick
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[*] posted on 12-8-2019 at 00:20
How to make a 1 Mole Sodium Hydroxide (NaOH) solution.


Hi All,

I was wondering of someone could help me out here. I am not finding the information I am looking for on the forum or on the web.

I would like to make a 1 Mole Solution of Sodium Hydroxide (NaOH). By itself that doesn't sound like the most complicated of tasks and there is a good chance that I am overcomplicating things.

However, I am living in Thailand and, especially at this time of the year (May - October), it is very hot and very humid. I noticed that NaOH flakes were quickly getting moist. To the point where you can see the flakes getting wet, producing fumes and getting hot. And all that just because of the humidity. I do not recall this behaviour from when I was still in The Netherlands though. In Holland it is a lot cooler and less humid most of the times. So I started to read up a little more on this and all I can find that it is normal behaviour from NaOH to absorb water.

How does this effect making a 1 Mole solution? I can not assume that 40 grams is actually 40 grams of NaOH because of the high water content? I tried to see if drying is an option. And well, I guess it is, but not very recommended because of the aggressive behaviour of NaOH when in its liquid state.

Am I overcomplicating things by looking into this and can it be ignored? Or is it a justified concern and is there a method (Simple ? :D ) to deal with this?

Looking forward to hear from you,


Joey
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[*] posted on 12-8-2019 at 03:22


It depends on the purpose for the 1m NaOH solution, if you are using it to provide strongly basic conditions then I can't see it making too much difference.

If you need the NaOH for a reaction (ie: it is consumed) then having less can affect the yield or too much may effect purity depending on the product.

Hard to give a solid answer without knowing your purpose.
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[*] posted on 12-8-2019 at 03:38


assuming you are starting with anhydrous stock NaOH pellets, you just need to weight the right amount fast, it won't be super accurate, but it can be used. if your source of NaOH is already wet, well you can't know the water concentration, so it should be used only for qualitative reactions or just to basify things in the ballpark




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[*] posted on 12-8-2019 at 04:02


Ugh! NaOH isn't able to be measured precisely by mass due to it's hygroscopicity, but what your describing goes beyond the usual difficulty. That's a legitimate problem if you're planning to use the solution for anything requiring any sort of accuracy of measurement. The easiest fix would be to mix up a fairly concentrated solution, do a rough titration, and then dilute as necessary. This could be done with technical grade acid and a Beryl pipette if nothing better is available.

If you have a balance of sufficient resolution you could also determine the concentration by referencing the density of your solution against an appropriate table. And if that's not an option you could just mix NaOH in water until it won't dissolve any more, decant the supernate, and dilute based on the maximum solubility for the temperature. It's approximately 6M as I recall.

If you have a burette and a good standard (sodium hydrogen phthalate works well as it's cheap and not hygroscopic) you can then standardize your solution. Or not, if you don't need more than 1 significant figure. If you do, keep in mind that the temperature of your solution will effect it's volume.




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[*] posted on 12-8-2019 at 04:54


Quote: Originally posted by Felis Corax  

And if that's not an option you could just mix NaOH in water until it won't dissolve any more, decant the supernate, and dilute based on the maximum solubility for the temperature. It's approximately 6M as I recall.


Thanks Felis.

Had several suggestions by now. In most cases it will suffice to just make sure I use fresh NaOH from an unopened package. This shouldn't be much of an issue considering its price.

But if I need more precision, I think I will use the quoted method. It is easy to control and maintain the temperature. The 6 Mole I will check, but I have a feeling that this is very much temperature dependant. Maybe I can use a temperature with a nice round Mole number and use this as a starting point when diluting to 1 Mole. According to Wikipedia I get 10+ moles at 0 degrees C and nearly 30 Moles at 20 degrees C. I also found 75 Moles at 70 degrees C. These are both nice round numbers, but 75 Moles sounds crazy. I need to do more homework first I guess. In addition, I also think such a high concentration at this temperature is not very healthy. The 70 degrees is easily reachable though because of the exothermic reaction. Maintaining it after that shouldn't be an issue either. Would need to add NaOH slowly though in order not to exceed the 70 degrees I think.

But anyways, I have been helped a great deal and for this I say thank you all.


Joey

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[*] posted on 12-8-2019 at 06:59


I think that method is a good idea, but it goes a little far in my opinion. Dissolving that much NaOH will greatly heat up the water and use a lot of material. Instead I would just dissolve a bit more than you think you need, then dilute down a little. So for example if you want 40g of NaOH to make a 1 molar solution, dissolve something like 60g of your material, titrate against HCl or another strong acid to determine actual molarity, then use M1V1 = M2V2 to dilute down to your desired concentration. Uses less water and NaOH, but does introduce the extra step of titration as long as you're comfortable with that.
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[*] posted on 12-8-2019 at 08:26


Quote: Originally posted by MrHomeScientist  
I think that method is a good idea, but it goes a little far in my opinion. Dissolving that much NaOH will greatly heat up the water and use a lot of material. Instead I would just dissolve a bit more than you think you need, then dilute down a little. So for example if you want 40g of NaOH to make a 1 molar solution, dissolve something like 60g of your material, titrate against HCl or another strong acid to determine actual molarity, then use M1V1 = M2V2 to dilute down to your desired concentration. Uses less water and NaOH, but does introduce the extra step of titration as long as you're comfortable with that.


Sure, but I was just using easy numbers. I like the idea of titration. Never done it though. But it was on my list, so this is a good reason to give it a try. At least I will have learned something new again. lol.

Joey
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[*] posted on 12-8-2019 at 08:57


And here I thought concentrated NaOH was 6M. Hehehe. Ooops! Way to make myself an object lesson on the importance of checking before posting. :D

MrHomeScientist is right, titration is the way to go if you can get your hands on some strong acid of reasonably known concentration and an indicator such as phenolphthalein or methyl orange. As an added bonus, titration an important skill for the amateur chemist, and not hard with the level of accuracy needed for a bench solution.

If you do make a saturated solution don't try to work with it at elevated temperatures. Nothing about the words "scalding hot 75M NaOH" should make you happy. Just take a relatively small quantity of water, add enough NaOH that you should be safely above the saturation point for whatever brutal value constitutes room temperature in Thailand this time of year, and mix thoroughly. A stir plate is your friend here, but if you don't have one you can at least take advantage of the exothermic nature of the reaction to make dissolution faster/easier.

Once you've dissolved all the NaOH you can, let the solution stand long enough to equilibrate with room temperature. There should be some precipitate as the solubility of NaOH goes down. Let this settle completely then carefully decant off the supernate. Dilute as discussed above and and revel in your success.

And do keep in mind that I'm basically the queen, or at least duchess, of overcomplication. Also, I'm suffering from mad chemistry withdrawal after around 5 months of being labless. My judgement is not to be trusted! ;)




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[*] posted on 12-8-2019 at 09:32


Just out of Curiosity one more question though. Can a Liquid in general or in this case a solution of NaOH be hygroscopic? And if yes could this be to the extend that it may significantly effect the concentration of the solution?

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[*] posted on 12-8-2019 at 09:43


Quote: Originally posted by Felis Corax  

Once you've dissolved all the NaOH you can, let the solution stand long enough to equilibrate with room temperature. There should be some precipitate as the solubility of NaOH goes down. Let this settle completely then carefully decant off the supernate. Dilute as discussed above and and revel in your success.


Is there a reason not to dilute it before cooling down? Seems to me that I would simply avoid the risk of precipitation and save the time for a new set of calculations not to mention the time savings on the cooling down. My feeling says it is a more direct approach.

Joey
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[*] posted on 12-8-2019 at 12:58


Several reasons, actually, and I'll go into some detail, but the core logic is this: Performing a temperature-sensitive procedure with a solution that's not at thermal equilibrium with it's environment adds complexity and potential for error. Sometimes doing so is necessary; for this procedure it's not even useful.

To start with you're going to have undissolved NaOH. That's not a problem, it's how you know that your solution is fully saturated. This can come from precipitate, or from adding NaOH until no more can dissolve, but either way it's going to have to be dealt with.

This means either decanting or filtration. Decanting requires all the solid particles to settle to the bottom of the beaker, so you have to let it sit anyway. In theory you could maintain temperature with a hotplate or other heat source, but it'll result in a temperature gradient forming between the top and bottom of the beaker. I guess you could decant before the solution reaches room temperature, provided you wait till all the precipitate settles and then measure the temperature. I wouldn't recommend it, but it could be done.

If you filter, which now that I think about it is probably better than decanting, you don't want to do it hot. Hot filtrations are a bother at the best of times, and doing one with a saturated solution guarantees loss. Some solute will invariably precipitate out as the solution cools from contact with the filter funnel, and even with the air. The hotter the solution the greater the temperature differential, and so the greater the rate of heat exchange.

But if that's not a good enough reason, mixing a solution to the point of saturation isn't as easy as you might imagine. Particularly if you don't have a stir plate to do all the work for you. The closer to saturated the solution the slower the rate of dissolution, until it reaches complete saturation and the rate becomes zero. But if you're going to let the solution cool after mixing you don't have to achieve saturation. In fact, depending on the temperature your solution reaches, you don't even need to get close. So while letting the solution cool to room temperature may take longer, it will certainly take less work.

Third we have safety. NaOH is caustic and it's reactivity increases with both temperature and concentration. Working with 75M NaOH @ 70℃ isn't something to be taken lightly, particularly as it can release caustic vapors. I don't know the exact level of risk here as SDSes and similar documents are usually worded in vague, ominous tones without reference to specific conditions or concentrations, but I'd wear thick 12" or longer gloves, a respirator, splash goggles, a face shield, and a chemical apron if I needed to handle such a solution. For what it's worth my fiance agrees with this level of precaution. He works in nuclear power and has a pretty good handle on chemical safety.

And finally, there's absolutely no need to rush this procedure. Or babysit it. Just mix it up and leave it to equilibrate. I recommend using the time to go to the grocery store and buy all the green tea kitkats you can lay your hands on. Patience is very important in chemistry. Also precision, persistence, perspicacity, proper precautions, planning procedures...

I'll stop now. :D

Quote: Originally posted by JoeyJoystick  
Just out of Curiosity one more question though. Can a Liquid in general or in this case a solution of NaOH be hygroscopic? And if yes could this be to the extend that it may significantly effect the concentration of the solution?

Joey


Hygroscopic liquids are absolutely a thing, a classic example being sulfuric acid. A brief google search reveals that NaOH solutions are both hygroscopic and prone to absorbing CO2 out of the air. I'm strongly inclined to believe this won't occur at anything like a rate sufficient to render the procedures discussed in this thread ineffective, but I don't have any hard data to back that up.




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[*] posted on 12-8-2019 at 23:23


A simple method, if you have a scale of decent accuracy, is the following:

- Take a small jar, having a good screw cap. Weigh the empty and dry jar, including its cap.
- Quickly pour solid NaOH pellets from a freshly purchased bottle into the jar, almost to the rim, and immediately put the cap on it and seal it.
- Now you can weigh again. No need to hurry, because the cap prevents absorption of water and only little humid air is inside the jar.
- The weight must be determined accurately, the precise amount is not critical, as long as it is known at decent accuracy.
- The weight of NaOH is the second weight (jar + NaOH) minus the first weight (empty jar).
- Now, open the bottle and dissolve in water. Any absorption of water is no issue anymore. Be sure to dissolve all of it.
- Top up the liquid (while mixing well) to a known measured volume in order to know the precise concentration.


[Edited on 13-8-19 by woelen]




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[*] posted on 13-8-2019 at 11:40


The best way if you have the equipment/expertise is to make a concentrated solution of NaOH. This is because commercial NaOH almost always contains some carbonate and that is relatively insoluble in concentrated NaOH. Allow it to settle and titrate an aliquot of the supernatant to determine its concentration with standard acid. Obviously for this method you need an acid of known concentration first. Sulphamic acid can be directly weighed or standard solutions of HCl are available. Then you can dilute the rest of the NaOH down to 1 Molar.

[Edited on 13-8-2019 by nezza]




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[*] posted on 13-8-2019 at 12:50


Quote: Originally posted by Felis Corax  

Third we have safety. NaOH is caustic and it's reactivity increases with both temperature and concentration. Working with 75M NaOH @ 70℃ isn't something to be taken lightly, particularly as it can release caustic vapors. I don't know the exact level of risk here as SDSes and similar documents are usually worded in vague, ominous tones without reference to specific conditions or concentrations, but I'd wear thick 12" or longer gloves, a respirator, splash goggles, a face shield, and a chemical apron if I needed to handle such a solution. For what it's worth my fiance agrees with this level of precaution. He works in nuclear power and has a pretty good handle on chemical safety.
.


I can chime in regarding that. I make a lot of sodium silicate, which for me usually involves dumping NaOH into boiling water (making it flash boil, yeah, but a little at a time just makes it a good mixing action). I continue to add NaOH until it stops violently boiling, indicating that it's nearing saturation. At this point it's >150°C and so saturated it's like a syrup. I've spilled drops of this solution on my hands and arms on several occasions. The worst I've gotten from it is small drop sized blisters, and only because I didn't wash it off immediately and let it sit there for >30 minutes.

As far as I know, no acid or base exists that will hurt your skin through caustic action in less than a couple of minutes. Just calmly wash it off, preferably neutralize it, and carry on. Eyes of course are a completely different subject, they don't have skin on them and will definitely be fucked right up from a caustic splash.

As for breathing the fumes, during my procedure described above which has to be the worst case in every way, it's not too bad. I prefer doing it outside since NaOH ruins basically everything it touches, but I have done it in the kitchen and as long as you don't stick your face right above the action a cough or two is the worst I've had from it.

So just my two cents for a more nuanced view on the dangers of sodium hydroxide. Gloves won't hurt, but just have some common sense, wear goggles, and it'll be fine.
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[*] posted on 13-8-2019 at 20:29


Quote: Originally posted by Junk_Enginerd  


So just my two cents for a more nuanced view on the dangers of sodium hydroxide. Gloves won't hurt, but just have some common sense, wear goggles, and it'll be fine.


Hi Nerd,

I am sorry, but I do not think this is very helpful and accurate. We're talking about one of the most dangerous alkaline solutions at high temperature. The temperature alone justifies proper PPE and than you get the solution on top of that which, by the way, at that temperature, is way more dangerous.

As far as other chemicals go, think of HF. Rinsing it with water won't even help you and you will need special medication/treatment if you get a spill on your body.

Anyways, on a forum that is accessible to people of all backgrounds, I think it is not wise to downplay safety risks in general.

I am not a chemist. I have, however, worked in the oil industry since I was 16 years old and as of yet never had a single accident or even an incident. We used to work a lot with chemicals and on occasions, such as with HF, we used to bring our own medication along and instruct the nearest doctor...

As far as your comments go, the following.

When you prepare your PPE it is very important that you consider a worse case scenario. In this case that would be that a bottle of boiling NaOH falls down and brakes and gets splattered all over you. You get a fright and fall and break your leg. Your wife is cooking in the kitchen and can't hear you and you are lying there for easily 30+ minutes. And there you are, lying on the floor wishing you had taken the time to put on some proper PPE.

And don't tell me that it is an unlikely scenario. The bottle falling is already an unlikely scenario. But when things go wrong they normally go wrong in pairs.

Quote: Originally posted by Felis Corax  

Third we have safety. NaOH is caustic and it's reactivity increases with both temperature and concentration. Working with 75M NaOH @ 70℃ isn't something to be taken lightly, particularly as it can release caustic vapors. I don't know the exact level of risk here as SDSes and similar documents are usually worded in vague, ominous tones without reference to specific conditions or concentrations, but I'd wear thick 12" or longer gloves, a respirator, splash goggles, a face shield, and a chemical apron if I needed to handle such a solution. For what it's worth my fiance agrees with this level of precaution. He works in nuclear power and has a pretty good handle on chemical safety.
.


So when Felis is trying to create safety awareness, than this should be considered good advice. Thanks Felis.

And personally, I would add the following.

- Consider taping the gloves to you sleeves. same with boots.
- I want to reiterate the importance of both googles and face shield because the face tissue is very sensitive skin tissue.
- Do not work alone!
- Have a shower or other solution for rinsing/washing down available.

And by the way, also thanks a lot for your explanations earlier. You've been of great help.

And when you work with high temperatures, than this should be taken in consideration as well.

Please do not play down safety.

Joey
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[*] posted on 13-8-2019 at 21:41


"... a bottle of boiling NaOH falls down and brakes and gets splattered all over you. You get a fright and fall and break your leg. Your wife is cooking in the kitchen and can't hear you and you are lying there for easily 30+ minutes. And there you are, lying on the floor wishing you had taken the time to put on some proper PPE... " While preparing to die a most horrid and painful death because the lye already dissolved your skin and eats its way into your flesh. Blood covers everything as you are wriggling away in the floor in agony. You are sinking into coma due to the shock reaction while your beloved still sings in the kitchen merrily with Sinatra with earpieces in her ears : "singing in the rain" and puts together your favourite Chicken Tikka Massala - that you won't eat anymore.... :(


I don't want to downplay the risks of our hobby but if a routine thing - making 1M NaOH solution - leads to 15 posts with such a dire outlook then many of us should consider giving up and start collecting stamps!

Woelen gave the probably most usable method. Vial with a cap, two measurements, dissolution, dilution, problem solved.

The op did not even bothered to mention the required accuracy of the concentration of the solution!

It does make a bit of difference if he wants that 1M between somewhere 0.8 - 1.2 M or in the 0.995 - 1.005 range!!! In the first case it does not even require the closed vials, not even in Thailand's humid air. In the later case I would not bother too much either because that kind of accuracy requires titration(s) anyway. And what if your NaOH solution turns out to be 1.086 M ? Does it interfere with the intended usage?

"forest from trees" comes to mind watching this thread :)





[Edited on 14-8-2019 by Pumukli]
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[*] posted on 14-8-2019 at 06:59


Quote: Originally posted by nezza  
The best way if you have the equipment/expertise is to make a concentrated solution of NaOH. This is because commercial NaOH almost always contains some carbonate and that is relatively insoluble in concentrated NaOH. Allow it to settle and titrate an aliquot of the supernatant to determine its concentration with standard acid. Obviously for this method you need an acid of known concentration first. Sulphamic acid can be directly weighed or standard solutions of HCl are available. Then you can dilute the rest of the NaOH down to 1 Molar.

[Edited on 13-8-2019 by nezza]

This is an excellent point that I hadn't considered. There's a benefit to making a concentrated solution, after all!


That reminds me of one of my first videos where I did a titration of hardware store HCl against NaOH. I used a large amount of the raw, concentrated acid (because I didn't know any better), and "discovered" that the NaCl produced was insoluble in the concentrated HCl! Nowadays I would take much smaller samples and dilute them to save on reagents, but that was kind of a fun accident.
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[*] posted on 14-8-2019 at 09:14


Wow, this got dark all of a sudden. Potential agonizing death is one thing, but there's no need to bring up philately! Jeepers! :o

It's nice to know that a droplet of 150℃ saturated NaOH solution takes a while to do noticeable levels of damage to the skin. That's actually useful information to have, and not the sort of thing safety documents tend to mention. Probably a liability thing.

I'm still inclined to err on the side of caution, especially with chemicals for which I don't have a source for credible and applicable experimental or experiential data. This is just good practice. Also, I enjoy not experiencing pain.

For anyone interested, NileRed has a video where he pours some common acids on his skin. It's quite informative, especially given the amount of misinformed opinions I found while looking into the subject. I've always heard, for example, that concentrated sulfuric acid causes chemical burns almost instantly... apparently not!

I don't want to downplay safety issues; it's good to wear more protective gear than is strictly necessary and plan for worst case scenarios, and I'd still wear most if not all of that safety gear I mentioned. But it's not so good to disseminate the sort of exaggerated or unsubstantiated risk assessments that seem to be endemic to discussions of chemical safety.

I feel a little stupid for wording my assessment of hot concentrated NaOH as strongly as I did without actually having any hard data on the subject. I'd feel like a right idiot if I'd passed on that pseudofact about concentrated H2SO4 causing near-instant chemical burns. It's exactly the sort of thing scientists, even amateurs, are supposed to know better than to do.

Besides, I'm pretty sure exaggerating safety concerns is known by the state of California to cause cancer or reproductive harm... :cool:




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[*] posted on 16-8-2019 at 10:23


Quote: Originally posted by JoeyJoystick  
Quote: Originally posted by Junk_Enginerd  


So just my two cents for a more nuanced view on the dangers of sodium hydroxide. Gloves won't hurt, but just have some common sense, wear goggles, and it'll be fine.


Hi Nerd,

I am sorry, but I do not think this is very helpful and accurate. We're talking about one of the most dangerous alkaline solutions at high temperature. The temperature alone justifies proper PPE and than you get the solution on top of that which, by the way, at that temperature, is way more dangerous.

As far as other chemicals go, think of HF. Rinsing it with water won't even help you and you will need special medication/treatment if you get a spill on your body.

Anyways, on a forum that is accessible to people of all backgrounds, I think it is not wise to downplay safety risks in general.

Please do not play down safety.

Joey


On the contrary, it is very accurate. It is based not on some blown up safety data I've read somewhere, but from my own first hand experience.

It is indeed one of the most dangerous alkaline solutions, especially when hot. It is also one of the most, if not the most caustic chemical to human tissues. This does not mean it is one of the most dangerous chemicals. Turns out that the most caustic chemical just isn't instant death and agony. It is moderately dangerous, nothing more and nothing less.

Hydrofluoric acid is certainly a dangerous animal, and requires stringent safety measures. And this actually relates to my point, especially considering that you say the forum is accessible to people of all background. When extreme caution is recommended, and people turn on the big red alert against something I would place on a solid "medium" on the danger scale, people may think that something like sodium hydroxide is about as bad as it gets. The reality is that sodium hydroxide is nothing compared to the real scary chemicals like HF, mercury compounds etc. Once they realize sodium hydroxide actually wasn't the big bad wolf it was touted to be, they may take further warnings less seriously.

Imagine taking the scenario a little further and replacing "sodium hydroxide" with "sodium bicarbonate". No cautionary statements would technically be false or wrong. Bicarb is also caustic to skin, although it needs some time to act, and it is an irritant and can burn you in a hot concentrated solution. Protective gear would certainly make any accidental outcome better. But if you went and stated that again and again, no one would take anything you say seriously. Not even when the danger is very real.

Because of this, I will always downplay safety as long as people are overplaying safety. Way too few people do this, and it leads to important dangers and information not being taken seriously.

Quote: Originally posted by Felis Corax  

It's nice to know that a droplet of 150℃ saturated NaOH solution takes a while to do noticeable levels of damage to the skin. That's actually useful information to have, and not the sort of thing safety documents tend to mention. Probably a liability thing.


Yes, and that was my point exactly. If you do not know where the actual "danger limit" is, you may get stuck in an overly cautious methodology which substantially hinders getting anything done. Worse, you may also be too close to "too dangerous" without even knowing it.

I'm really sad that safety documents are so worthless. They err on the side of caution to such extreme lengths that the information often is completely useless. You risk ignoring the actual worthwhile safety risks along with the rest of the garbage.

Quote: Originally posted by Felis Corax  

I'm still inclined to err on the side of caution, especially with chemicals for which I don't have a source for credible and applicable experimental or experiential data. This is just good practice. Also, I enjoy not experiencing pain.


That's never a bad approach, so it's a good default...

But I do get annoyed when people spread overt fear of chemicals that maybe aren't that dangerous. Again, it leads to the information getting hard to decipher when you bottom out the danger scale and basically end up saying calcium chloride, sodium hydroxide and hydrofluoric acid are all death. Then some half newbie comes along and remembers from experience that calcium chloride wasn't very bad at all, so that should mean hydrofluoric acid is probably pretty safe too.

Quote: Originally posted by Felis Corax  

For anyone interested, NileRed has a video where he pours some common acids on his skin. It's quite informative, especially given the amount of misinformed opinions I found while looking into the subject. I've always heard, for example, that concentrated sulfuric acid causes chemical burns almost instantly... apparently not!


It's a great video, and I had it in mind during my previous post. Knowing exactly how long it takes for an acid to become dangerous is very valuable, since you'll know there's no need to panic in case of an accident, and that may help you make smarter decisions.
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[*] posted on 18-8-2019 at 04:08


I fully agree with this! Spreading fear about moderately dangerous chemicals is a dangerous act in itself.

I have a few chemicals, which really are at a complete different level of danger. Just to name a few:
Extremely corrosive. These REALLY destroy skin in a fraction of a second! Never get one of these on your skin!
- oleum
- chlorosulfonic acid
At least, the above chemicals are "honest". Their action is immediate and their action also is apparent towards other materials (e.g. paper, towels, wood, other chemicals).

Moderately concentrated HF is another beast, it is even more dangerous. Looks quite tame, but it REALLY kills!




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[*] posted on 18-8-2019 at 08:24


Quote: Originally posted by Junk_Enginerd  

On the contrary, it is very accurate. It is based not on some blown up safety data I've read somewhere, but from my own first hand experience.


Hi Nerd,

I saw the responses coming in and gave myself a few days to reflect on this.

You know what, I actually agree with you to a degree. I did not intend to scare the masses at all. But let me explain where I am coming from.

I have been living and working in developing countries for the last 15+ years. The reason these countries are developing is for a big part education. And since the responsibility for a job often comes to the likes of me, the foreigner who is supposed to know what he is talking about, I tend to be a bit more cautious. It kind of paid of since I never had a work related accident (other than falling asleep in the car...) nor did anyone working with me or for me ever had an accident. As I am writing this I am actually in China for a small job. And today there was a small incident here where 2 guys were in a confined space. The manhole watch had lunch, so he left and locked the door with these 2 guys inside... These kind of things happen everywhere, but they happen a lot more often in underdeveloped countries with lower levels of education. Hence my cautiousness.

The reason I initially posted was not so much of the NaOH as such, but more the high temperature and the concentration you were talking about.

A guy I new very well had an accident with NaOH and got a full load straight in his face. 2 weeks in the hospital and they managed to save his vision.

Myself, when I was 12 or 13 years old, had an incident with battery acid. Took an old car battery to my hobby room and placed it on my chair in the summer. When the temperatures were back to normal and I started to continue building my model airplane I first put the battery on the floor and I sat down on my chair. Little did I know that the battery was leaking and the cushion was soaked with acid. My ass was sore for days when I realized I was getting itchy. And by then it was obviously too late. I am laughing here reading what I wrote, but hey, I was young and still had much to learn.

So I fully agree that risks should not be exaggerate, but it should also not be downplayed.

And in this context, one of the better safety slogans I think still is: 'Better Safe than Sorry'.

Anyways, my apologies for giving the wrong impression, this was not my intention at all. At the same time I hope you understand better where I am coming from as well though.


Joey



[Edited on 18-8-2019 by JoeyJoystick]
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[*] posted on 18-8-2019 at 08:36


Quote: Originally posted by woelen  
A simple method


Hi Woelen,

Thanks a lot for your method as well.


Joey
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[*] posted on 18-8-2019 at 20:19


Quote: Originally posted by JoeyJoystick  
And in this context, one of the better safety slogans I think still is: 'Better Safe than Sorry'.


I'm fond of "safety third."




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[*] posted on 18-8-2019 at 21:15


Quote: Originally posted by JoeyJoystick  
<snip>

So I fully agree that risks should not be exaggerate, but it should also not be downplayed.

And in this context, one of the better safety slogans I think still is: 'Better Safe than Sorry'.

Anyways, my apologies for giving the wrong impression, this was not my intention at all. At the same time I hope you understand better where I am coming from as well though.


Joey]

Point taken. But the original question was about a 1 molar solution. This is not concentrated by any stretch. It would not be sensible to conflate the two.
One of the ongoing discussions here is on how chemicals are perceived by the public. Apportioniong the right level of risk to the situation is essential.




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[*] posted on 18-8-2019 at 22:22


Quote: Originally posted by JoeyJoystick  

Myself, when I was 12 or 13 years old, had an incident with battery acid. Took an old car battery to my hobby room and placed it on my chair in the summer. When the temperatures were back to normal and I started to continue building my model airplane I first put the battery on the floor and I sat down on my chair. Little did I know that the battery was leaking and the cushion was soaked with acid. My ass was sore for days when I realized I was getting itchy. And by then it was obviously too late. I am laughing here reading what I wrote, but hey, I was young and still had much to learn.


I can remember playing with battery acid. It was an excellent learning experience. A day or so later my clothing developed holes everywhere it had been contaminated with the acid. I was surprised just how sloppy I had been. Even the slightest contamination with dilute sulfuric acid on cotton clothing damages it. As the acid drys it becomes more concentrated because it is only the the water that evaporates leaving more concentrated acid that decompose the cotton.




i am wg48 but not on my usual pc hence the temp handle.
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