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Lim Y K
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Pure water is not an electrolyte. This is because the hydrogen atoms and oxygen atom will not dissociate into individual charged particles. Why won't they dissociate?
Isn't the actual ionic equilibrium ##2H_2 O (l) ⇔ H_3 O^{+} (aq)+ OH^{-} (aq) ## ? If I remember correctly, H+ ions are just used instead of hydronium ion for simplification of the equation, but the actual equation is the one above.tommyxu3 said:Besides, that's not two atoms'( ##\text{H}## and ##\text{O}## ) dissociation, but ##\text{H}^+## and ##\text{OH}^-.##
Ahh, I see. But is it safe to say that n is not large? I mean after all, you'll eventually crowd up the entire area around the H+ ion so that the repulsion between the lone pair of electrons on the O atoms of water molecules solvating the ion and the lone pairs on the O atoms of 'unlinked' water molecules is greater than any attractive force the 'unlinked' water molecules might feel toward the H+ ion, preventing these 'unlinked' molecules from solvating the H+ ion as well.Borek said:Protons can be solvated by several water molecules (so there exists whole series of cations of the general formula H2n+1On+). H+ is about as good as H3O+ IMHO - works OK as a symbol, doesn't reflect the reality. Add to that fact that OH- is not isolated in the solution, but solvated as well (yielding H2n+1On+1- anions), and you should start to see the picture
PWiz said:But is it safe to say that n is not large?
Wow, that's pretty cool. Looks like I've got something to show to my Chem teacherBorek said:Depends on what counts as "large". Some research suggests structures with n up to 20.
https://en.wikipedia.org/wiki/Hydronium#Solvation
Borek said:Protons can be solvated by several water molecules (so there exists whole series of cations of the general formula H2n+1On+). H+ is about as good as H3O+ IMHO - works OK as a symbol, doesn't reflect the reality. Add to that fact that OH- is not isolated in the solution, but solvated as well (yielding H2n+1On+1- anions), and you should start to see the picture
DrDu said:I think the difference is that in H3O+, the proton is covalently bounded to a water molecule while the additional water molecules in the larger clusters are bound via hydrogen bridges.
The reason why water molecules do not dissociate easily is because of the strong bonds between the oxygen atom and the two hydrogen atoms. This bond, known as a covalent bond, is very stable and requires a significant amount of energy to break. Additionally, the small size of the hydrogen atoms makes it difficult for them to break away from the oxygen atom.
The dissociation of water molecules can be affected by a number of factors such as temperature, pressure, and the presence of other substances. Higher temperatures can provide the energy needed to break the bonds between the hydrogen and oxygen atoms, while increased pressure can push the molecules closer together, making it easier for them to dissociate. Other substances, such as acids and bases, can also influence the dissociation of water by interacting with its molecules.
Yes, under certain conditions, water molecules can dissociate. For example, when an electric current is passed through water, it can cause the water molecules to split into positively charged hydrogen ions (H+) and negatively charged hydroxide ions (OH-). This process is known as electrolysis. However, this dissociation is only temporary and the ions will quickly recombine to form water molecules again once the current is removed.
Water is considered a stable molecule because it has a very low tendency to dissociate under normal conditions. The strong covalent bonds between the hydrogen and oxygen atoms make it difficult for the molecule to break apart. Additionally, the shape of the water molecule, with the two hydrogen atoms bonded to one side of the oxygen atom, also contributes to its stability.
The stability of water molecules is crucial for life on Earth. If water was easily dissociated, it would not be able to form the hydrogen bonds that are essential for many biological processes, such as protein folding and DNA replication. Additionally, the stable nature of water allows it to act as a solvent, providing an ideal environment for chemical reactions to occur in living organisms.