Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Dck140130 on April 08, 2022, 06:31:48 PM
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Hello,
Is this correct?
HCl(aq) + H20 (aq) :rarrow: H30(aq) + Cl(g)
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Using GOOGLE and searching on the left hand side of your equation
HCl(aq) + H20 (aq)
and selecting the choice from a well known source
Britannica
chemical reaction - The Brønsted-Lowry theory - Encyclopedia ...
we are directed to
The Brønsted-Lowry theory
https://www.britannica.com/science/chemical-reaction/The-Bronsted-Lowry-theory (https://www.britannica.com/science/chemical-reaction/The-Bronsted-Lowry-theory)
which shows a different formula than what you had in your post.
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Charges!
And once you will get charges right you will see there is no gaseous product.
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It was really not correct.
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@billnotgatez thank you again! The way you answer also helps instruct on how to find answers despite my naivety.
Thank you @Borek for the additional education. I've been solely focused on how to of obtaining product and appreciate knowledge of the why.
@rolnor... low blow, no cookie for you.
Wondering if I can just boil off the the Cl and be left with H3O+?
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Wondering if I can just boil off the the Cl and be left with H3O+?
Told you to not ignore the charges, they completely change the situation.
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Yes, I was not nice but its also true what I wrote. You are lacking skills on a very fundamental level and need to do some reading, thats just a fact, no harm intended. If this was a coocking-forum your question would be on the same level as "should I use water when I boil pasta?" Do some reading. Here: https://en.m.wikipedia.org/wiki/Acid
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Thank you @rolnor and @Borek. pointing to missing knowledge helps. I am aware of my naivety but am trying to perform a recipe and am not trying to reread my chemistry textbooks. I will try to figure out what it means to not ignore the charges (obviously I understand electrons are negative, protons or positive, and valence shells have a maximum that effects whether they can bond and the strength of the bond) and will read the Acid wiki before I return to the forums. I have never understood the condescending nature of forum culture as though sharing knowledge should only begin once a person is at a certain level. As an electrical engineer, I would never treat someone as though they were wasting my time because they didn't understand number theory or boolean logic or even how to read an algebraic equation.
P.S. whoever took away a snack from me... ow
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I am usually not condesending, I wanted to be very CLEAR. It was tough love kind of.
I notice your enthusiasm and that is something very valuable, I hope I did not kill that.
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I will try to figure out what it means to not ignore the charges
In short: when writing reaction equation you need to write charges of the ions and make sure, they balance (so while sometimes H :rarrow: H+ is an acceptable shorthand, in general it is wrong as the charge appears from nowhere). In this very thread you started with an "equation" that contained things like H3O (doesn't exist as far as I am aware, it should be H3O+) and Cl (guessing from the context you meant Cl-). Cl and Cl- have fundamentally different properties - the first one occurs only in highly exotic condition of low pressure and high temperature, the latter is present in every water solution (including bath water, vodka and soft drinks) you dealt with in your life.
I have never understood the condescending nature of forum culture as though sharing knowledge should only begin once a person is at a certain level.
We have nothing against helping anyone, but we are often flooded with requests from kids not even bothering to open their textbooks yet hoping someone will help with their homework. The basic approach here is to give pointers, not answers.
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@rolnor, your tough love was effective despite my lack of appreciation. My use of "lowblow" and "no cookie" was meant to express my distaste somewhat in jest too. I am embarrassed as well for my laziness, naivety, and manner of handling your response. My motivation remains.
@Borek, thank you for the additional education. I was lazy in my notation and, similar to students looking for shortcuts, I admit that I am in the forums looking to be spoon fed as well.
I want to express my heartfelt gratitude that everyone even took the time to read and reply. The consequent rabbit holes I have traveled are going to take some time to organize and think more critically about before I am ready return with a well researched inquiry that is considerate to everyone's time here.
I think that we can conclude this thread with the following as a solution:
from @rolnor - the answer to my question is no
from @billnotgates - https://www.britannica.com/science/chemical-reaction/The-Bronsted-Lowry-theory shows that the reaction is dynamic (::equil::), albeit a product favored reaction, and that the Cl- in the product is the weak base and aqueous. That H2O is the base reactant in the Bronsted-Lowry reaction and that HCl is the strong acid reactant.
from @Borek - charges matter, and that https://en.m.wikipedia.org/wiki/Acid indicates that what makes HCl qualify as an arrhenius bronsted-lowry acid is that it readily donates a proton in the form of H+(aka protonation, protolysis). Since H2O is present, the H+ donated by the HCl, bonds with the H20 to form H3)+ and leaves Cl- in aqueous form, or as a solvent in the solution. Since HCl is a "strong acid" it readily dissociates in water. Since there is a 1:1 relationship between protonation of the HCl and H2O, HCl also falls into the category of monoprotic acid.
A link within the wiki recommendation from @Borek (https://en.m.wikipedia.org/wiki/Hydrochloric_acid) immediately reveals that H3O+ (hydronium) in fact constitutes the HCl with Cl- and they will likely form other hydrogen bonds with neighboring H2O molecules in a variety of ways. In the presence of enough H20 however, it is likely to entirely dissociate into H3O+ and Cl-. The wiki page also indicates that the mass fraction of the HCl effects physical properties such as boiling point. For example it indicates that the mixture will act as an azeotrope if the mass fraction 20.2% and this means that at the corresponding boiling point that the vapor will be maintain the same proportions that existed in the mixture. This point is somewhat related to my asking if I can just boil off the Cl- since the product of the Bronsted-Lowry reaction is favored and Cl- boiling point is significantly lower than H2O, but perhaps not so low that H30+ would not be denatured in the process. However, I consider the boiling point of H3O+ to likely be similar to H2O and well above that of Cl- since the bonds of the hydrogen and H+ are covalent with the O (not positive this point though). Certainly need to keep top of mind eutectic and azeotropic properties based on mass fraction it appears. It does not look like hydrogen bonds between H3O+ require much attention.
Other research makes it look like the most efficient way to remove Cl- ions is with Silver Nitrate to form precipitates and then filter. I would like to avoid introduction of more elements as it feels like steps away from the final product rather than towards. such is the game i guess.
ultimately the reaction i am trying to perform here I have attached an image of. My initial question was because I was trying to figure out how to make sure my reactants are combined in the presence of H+/H2O
additional answers I will need to discover is how to get rid of the diethyl ether in one of my reactants and where the heck the MgBr went.
Thanks again everyone.
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Great, but the scheeme in the bottom makes me puzzled, you should not have water or acid present when doing Grignard chemistry, that will quench the Grignard reagent.
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Cl- boiling point
No such thing, you are definitely confused somewhere.
Boiling point relates to liquids, there is no liquid composed of Cl- only. There are plenty of liquids (mostly solutions) in which Cl- is a component, but it is always accompanied by some positive ion, as the solution must be electrically neutral (think about repelling forces).
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I wonder, it should be possible to theoreticaly model neat Cl-, but the ions have the same charge so what would that substance be? Maybe a gas at roomtemp?
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Single ions, at very low pressure - yes. But once you get into practical amounts coulombic forces involved are enormous, so there is no way to keep it confined.
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And what happens if they are not confined, they will be become a very thin gas? It must be possible to model this.
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Simple physics.
But start by estimating force with which one mole of Cl- anions (so basically 96500 Coulombs) repels other mole of Cl- if kept at 1m from each other. Compare that number with the force with which Earth attracts Moon.
Good luck preparing sample of pure Cl- larger that just few atoms ;)
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So it will maybe be like an explosion if you gave a conc. sample and release the pressure. But will be a gas, afterwards, a very thin gas. I consider the force keeping the ions together is the gravity on earth. The coloumb force decrease with the squared distance so it will not be endlessly strong force repelling the ions.
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I consider the force keeping the ions together is the gravity on earth.
To some extent, but gases expand to occupy whole available volume.
The coloumb force decrease with the squared distance so it will not be endlessly strong force repelling the ions.
Have you compared the numbers I suggested you to calculate?
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No, but have you thought what happens if the ions are separated by 10cm? The coloumb forces are not so strong then. I am talking about really thin gas. You can have a beam of electrons that is dense, and these also repell with the same force as Cl- ions, this beam does not spread immediatly.
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Sure, doable, that's a high vacuum, interstellar plasma, whatever. That falls into what I call "exotic conditions". And it would still attract everything with positive charge, so it won't last.
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I sad thin gas, and I am was right. Read my updated post about electron beams.
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Electron beams and ion beams are confined and focused using strong electromagnetic fields. Once the field is gone, the ions diverge immediately.
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No, I have seen electronbeam that is a straight line without magnetic field. It was an experiment where you direct a electron beam on a rotor and this starts to spinn, it proves that electrons have mass.
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No, I have seen electronbeam that is a straight line without magnetic field.
And how was the beam generated?
Sure, once they leave the magnetic field they can travel together for a short time, but the beam diverges quite fast. In no way you could call it stable. It looks stable only because they move at high speed so they have no time to diverge before hitting the target. Electrons in an old CRT monitor travelled at speeds measured in tenths of c, it took them just a few ns to reach the target.
Again: do the calculation I suggested. Just a mole of ions, small fraction of what you have inside ;)
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@rolnor
The electron beam appears straight in the sense that you know where the beam is produced and you can draw a straight line between it and your target. But the beam is not perfectly collimated.
I thought to make an argument based on beam divergence angles. A laser (which shapes light by matter-based optics) has a beam divergence based on fundamental properties of light; a typical green laser pointer has divergence typically on the order of about a milliradian, or ~0.05 deg. See for example this one (https://www.edmundoptics.com/f/ultra-bright-green-laser-pointer-072c40a5/12610/) by Edmund Optics. All particle beams have divergence, not just lasers. I’m no expert but here’s an example of a divergence angle measurement (https://www.sciencedirect.com/science/article/abs/pii/S016890021931407X?via%3Dihub) on an electron beam (Kim et al 2020 Nuclear Inst. Methods Phys. A, 953, 163054): they measured approx. 2 deg. That’s several orders of magnitude higher divergence in a high-powered electron beam than an inexpensive laser pointer. I found similar values for some positively charged ion beams, e.g. here (https://aip.scitation.org/doi/10.1063/1.1143433) (Pai and Venkatramani, Rev Sci Inst. 1992, 63, 5234).
Now I have to stop and give you a big sarcastic thank you, rolnor. It was about this point I got lost for three hours reading about the physics of charged particle beams. At first I assume the large divergence in electron beams was due to simple Coulomb repulsion; squeaky clean argument. But (no surprise) it seems to be due to much more goofy quantum s#*$ than that. The article I linked to on electron beam divergence angles attributed the divergence to the property called ‘emittance’. So I looked that up and got thoroughly shot down the rabbit hole like I was fired from (ha) an electron gun. If you don't believe me, just google "particle beam emittance". Yikes. Anyway, long story short, the equations for transverse momentum components of the high energy beam emittance do indeed contain a factor proportional to the particle charge (example, but don't say I didn't warn you (https://uspas.fnal.gov/materials/10MIT/Emittance.pdf)), so … yeah... I guess I was kind of right. Even though it hardly feels like a victory 😉.
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But was I wrong?
Its nice that you go to such a length in your study of electron beams.
If coloumb forces in a beam would be enormous the electrons would still spread out even in a few nanoseconds, a magnetic field have this effect, this is how an old TV works to create the image in the screen?
You see the copper coil-wire in this image, the magnetic field generated spreads the beam If you get a ordinary permanent magnet close to a old TV-tube, the image gets distorted.
https://www.google.com/search?q=tv-tube&rlz=1C9BKJA_enSE868SE868&oq=tv-tube&aqs=chrome..69i57j0l3.6006j0j4&hl=sv&sourceid=chrome-mobile&ie=UTF-8#imgdii=zXZBc69bBUMnHM&imgrc=6CadaTBRK_Fv7M
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You state it would be a interstellar vaccum-gas. Thats a thin gas so why are you arguing? You agree with me obviously?
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Two people read your statements as "ah, these charges don't mean anything, nothing to fuss about", when the situation is exactly the opposite - they are the most important, game changing elements of the situation.