Sciencemadness Discussion Board

Chlorine or Bromine toxicity help!

Wrecking Bereserker - 2-4-2019 at 07:56

I'm just an amateur chemist and i don't own a fumehood
So im thinking does a table fan help with toxic gases when there is no wind outside
I'm planning to make some chlorine gas to perform halide test so is there anything i should be concerned about
I've previously made SO2,NO2,Br2 outisde have smelled than by mistake but I'm still doing well so why is there so much uproar about them being toxic?
Are Concentrated acids dangerous as they say in internet even for a short period of time and spills on hand because sometimes I've had some drops on my palms but i immediately wash so not much happens

MrHomeScientist - 2-4-2019 at 08:19

I always say that the most important thing is to respect your chemicals. You need not fear toxic chemicals or otherwise hazardous experiments; just make sure you understand what you are working with before handling it. Read the SDS for each chemical so you know what to watch out for. Carefully plan your experiment beforehand, and make a plan for what to do if (when) things go wrong. What's the worst case scenario? How would you handle it? Make sure to consider the safety of other people too - your fan might save you from chlorine, but is it blowing directly into the neighbor's window? Goggles and gloves are a must.

Working outside with a fan is definitely better than nothing; I've done that many times before. It's not perfect though, and if the wind does pick up it can blow fumes right back at you. Be prepared to escape to fresh air if you need to. An even better option is to design your apparatus such that no gases will escape. Use a sealed system that directs the gas to bubble into a wash bottle that neutralizes it, for example. (dilute NaOH for chlorine, specifically)

One whiff of a toxic gas won't kill you. It might make you feel ill for a while, depending on what it is. It's repeated exposure or exposure to high concentration that gets really dangerous. Obviously don't stick your nose in the flask and inhale deeply. One whiff of something diluted in air now and again isn't a big deal. Again, if you respect your chemicals and have a safety plan in place, these risks can be reduced.

As for acids, it depends on the acid and the concentration. 20% sulfuric acid won't do anything, but 98% is incredibly dangerous. Hydrofluoric acid is highly dangerous at any concentration. At the other end of the spectrum, some people wash their hands with dilute hydrochloric acid. As long as you rinse things off your skin promptly, in most cases you'll be fine.

There are of course exceptions to everything I've said, which is why you should read the SDS's before using any chemical and understand the risks you're taking first. Chemistry can be fun and very rewarding, but it also has its share of dangers. Moreso than most other hobbies, I'd say. You just have to be aware of them, and plan accordingly.

Sulaiman - 2-4-2019 at 08:27

I'm just an amateur chemist and i don't own a fumehood
neither do I
So im thinking does a table fan help with toxic gases when there is no wind outside
it would definitely help if there is NO wind
I'm planning to make some chlorine gas to perform halide test so is there anything i should be concerned about
if you are only doing a little testing the volumes that you create will be a low level hazard
I've previously made SO2,NO2,Br2 outisde have smelled than by mistake but I'm still doing well so why is there so much uproar about them being toxic?
because some people have to work in such environments daily
Are Concentrated acids dangerous as they say in internet even for a short period of time and spills on hand because sometimes I've had some drops on my palms but i immediately wash so not much happens
mineral acids if washed off promptly cause little long termskin damage
BUT CAN DAMAGE YOUR VISION IN THE BLINK OF AN EYE

Wrecking Bereserker - 2-4-2019 at 08:38

Quote: Originally posted by MrHomeScientist  
I always say that the most important thing is to respect your chemicals. You need not fear toxic chemicals or otherwise hazardous experiments; just make sure you understand what you are working with before handling it. Read the SDS for each chemical so you know what to watch out for. Carefully plan your experiment beforehand, and make a plan for what to do if (when) things go wrong. What's the worst case scenario? How would you handle it? Make sure to consider the safety of other people too - your fan might save you from chlorine, but is it blowing directly into the neighbor's window? Goggles and gloves are a must.

Working outside with a fan is definitely better than nothing; I've done that many times before. It's not perfect though, and if the wind does pick up it can blow fumes right back at you. Be prepared to escape to fresh air if you need to. An even better option is to design your apparatus such that no gases will escape. Use a sealed system that directs the gas to bubble into a wash bottle that neutralizes it, for example. (dilute NaOH for chlorine, specifically)

One whiff of a toxic gas won't kill you. It might make you feel ill for a while, depending on what it is. It's repeated exposure or exposure to high concentration that gets really dangerous. Obviously don't stick your nose in the flask and inhale deeply. One whiff of something diluted in air now and again isn't a big deal. Again, if you respect your chemicals and have a safety plan in place, these risks can be reduced.

As for acids, it depends on the acid and the concentration. 20% sulfuric acid won't do anything, but 98% is incredibly dangerous. Hydrofluoric acid is highly dangerous at any concentration. At the other end of the spectrum, some people wash their hands with dilute hydrochloric acid. As long as you rinse things off your skin promptly, in most cases you'll be fine.

There are of course exceptions to everything I've said, which is why you should read the SDS's before using any chemical and understand the risks you're taking first. Chemistry can be fun and very rewarding, but it also has its share of dangers. Moreso than most other hobbies, I'd say. You just have to be aware of them, and plan accordingly.


So for example if im reacting KMnO4+ConHcl to produce Cl2 gas and collect it using a tube fitted into a sealed rubber cap of test tube how can i make sure if the gas gets out it goes into NaOH and thanks for the lovely reply

MrHomeScientist - 2-4-2019 at 10:17

You could use a 2-hole stopper instead, so the gas would come in one hole and exit out the other to end up in the neutralizing solution. Here's a screenshot from my latest video to illustrate:

example.png - 499kB

The arrows are the direction of gas flow. That's for a different experiment than yours, but hopefully you get the point. I was producing nitrogen in the generator, drying it in the gas wash, and collecting it on the left. The suckback trap is an empty test tube between the different containers, in case the pressure changes and liquid is "sucked back" through the system. That stops the contents of the test tube from getting into the gas generator, and vice versa.

Edit: It's not very clear in the picture, but the glass tubes going through the stopper in the suckback trap don't go very far past the stopper. The right tube in the gas wash goes all the way to the bottom of the liquid, and the left tube stops right at the stopper. This forces the gas to bubble through the whole column of liquid in the gas wash. The short tubes in the suckback trap prevents anything from leaving the trap if it happens to get in there.

Your own setup depends on what exactly you are trying to do, of course! What "halide test" are you doing? Can you describe the procedure?

[Edited on 4-2-2019 by MrHomeScientist]

Wrecking Bereserker - 2-4-2019 at 10:31

Im gonna use Chloroform or any organic solvent with Iodide or bromide salts mixed in water.using the chlorine gas produced by the they oxidize into iodine and bromine and dissolves into the organic solvent

woelen - 2-4-2019 at 23:39

If you work outside and you produce small amounts, then I see no real risks. Chlorine and bromine both have strong smells and become intolerable at low concentrations. If you are outside you can always easily escape the gas by stepping back from your setup. Even when there is hardly any wind, outside there will be no real buildup of toxic gas concentrations.

I work comfortably and fairly routinely with small quantities of Cl2, Br2, NO2, SO2, H2S, NH3, PH3 and even the somewhat nastier HCl, HBr, vapor of CH3COCl, PCl3, PCl5, SOCl2, SO2Cl2. A small whiff of any of these gases or vapors does no real harm. Just do not inhale too much and do not inhale them frequently. All of these gases are very toxic, due to their immediate corrosive effect on your body. They are not strong systemic poisons. If I do experiments with these gases, outside, then I just step back when their smell becomes too strong and if I have to handle something on the setup, I step nearer, hold my breathe while doing my thing, and then step back again. Sometimes I smell some of the gas or get a little tingling in my nose or throat, but nothing more than that. If I step back then the effect is gone. Just to give you an example, see this thread:

http://woelen.homescience.net/science/chem/exps/PBr3_synth/i...

Lots of noxious gases, but no issue because I did this outside and did not get more than a few dilute whiffs of vapor.



I am much more reluctant to work with strong systemic poisons which can become airborne as gas or aerosol. Think of AsH3, H2Se or aerosols containing Hg-compounds, Tl-compounds, Cd-compounds, Be-compounds. These are not corrosive like HCl or Cl2, but they wreak havoc on all kinds of processes in your body and may also have long-term effects and may accumulate in body tissue. Some of them may increase the risk of cancer as well.

One special exception for me is working with HF. This is insidiously dangerous to work with. Even small amounts may cause very serious wounds, with delayed effect. I do have some 48% HF for several years already, but the number of experiments I did with this can be counted on the fingers of one hand. It is too risky to work routinely with that, it is one of the very few chemicals which I am somewhat scared of.